More open-source friendly docs

[kp-samuel-tam]

Description

This PR adds comprehensive manual page generation and improves help documentation for lightway tools. The changes include:

• Added new lightway-man package, running the binary will generate the manual pages
• Enhanced --help text with extensive documentation for both client and server
• man lightway-server is longer than lightway-server --help, with separate command_for_manpage() function
• Updated Earthfile to include this in build process, i.e. earthy +build-man

This paves the way for building open-source graded Debian packages.

Motivation and Context

Users needed comprehensive documentation for lightway tools beyond basic --config-file help output. Manual pages provide the standard Unix way to access detailed documentation, while maintaining concise help for quick reference. This establishes a proper documentation foundation for the project.

How Has This Been Tested?

• Verified manual page generation produces properly formatted documentation
• Confirmed both brief --help and comprehensive manual pages work correctly
• Tested that all packages compile successfully with the new dependencies
• Ensured license checks pass with the updated deny.toml configuration
• Validated Earthfile changes integrate manual generation into the build process
• earthy +build-man works

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• The correct base branch is being used, if not main

[github-actions]

Code coverage summary for db4d3cb:

Filename                                                     Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover    Branches   Missed Branches     Cover
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
lightway-app-utils/src/args/cipher.rs                              4                 4     0.00%           1                 1     0.00%           5                 5     0.00%           0                 0         -
lightway-app-utils/src/args/connection_type.rs                     4                 4     0.00%           1                 1     0.00%           5                 5     0.00%           0                 0         -
lightway-app-utils/src/args/duration.rs                            7                 7     0.00%           5                 5     0.00%          13                13     0.00%           0                 0         -
lightway-app-utils/src/args/ip_map.rs                             11                11     0.00%           3                 3     0.00%          15                15     0.00%           0                 0         -
lightway-app-utils/src/args/logging.rs                            14                14     0.00%           2                 2     0.00%          16                16     0.00%           0                 0         -
lightway-app-utils/src/codec_ticker.rs                            47                 7    85.11%          17                 4    76.47%         172                11    93.60%           0                 0         -
lightway-app-utils/src/connection_ticker.rs                       71                11    84.51%          28                 4    85.71%         279                11    96.06%           0                 0         -
lightway-app-utils/src/dplpmtud_timer.rs                          63                 7    88.89%          22                 4    81.82%         282                11    96.10%           0                 0         -
lightway-app-utils/src/event_stream.rs                             5                 0   100.00%           3                 0   100.00%          13                 0   100.00%           0                 0         -
lightway-app-utils/src/iouring.rs                                157               142     9.55%          23                17    26.09%         304               281     7.57%           0                 0         -
lightway-app-utils/src/metrics.rs                                  2                 2     0.00%           2                 2     0.00%           4                 4     0.00%           0                 0         -
lightway-app-utils/src/sockopt/ip_mtu_discover.rs                 23                23     0.00%           4                 4     0.00%          93                93     0.00%           0                 0         -
lightway-app-utils/src/sockopt/ip_pktinfo.rs                       4                 4     0.00%           1                 1     0.00%          31                31     0.00%           0                 0         -
lightway-app-utils/src/tun.rs                                     75                75     0.00%          22                22     0.00%          93                93     0.00%           0                 0         -
lightway-app-utils/src/utils.rs                                   13                13     0.00%           1                 1     0.00%          11                11     0.00%           0                 0         -
lightway-client/src/args.rs                                       29                29     0.00%          25                25     0.00%          32                32     0.00%           0                 0         -
lightway-client/src/io/inside/tun.rs                              36                36     0.00%           7                 7     0.00%          40                40     0.00%           0                 0         -
lightway-client/src/io/outside/tcp.rs                             48                48     0.00%          10                10     0.00%          45                45     0.00%           0                 0         -
lightway-client/src/io/outside/udp.rs                             66                66     0.00%          12                12     0.00%          65                65     0.00%           0                 0         -
lightway-client/src/keepalive.rs                                 275                38    86.18%          61                 8    86.89%         405                28    93.09%           0                 0         -
lightway-client/src/lib.rs                                       284               284     0.00%          30                30     0.00%         402               402     0.00%           0                 0         -
lightway-client/src/main.rs                                       52                52     0.00%           7                 7     0.00%         176               176     0.00%           0                 0         -
lightway-core/src/borrowed_bytesmut.rs                            86                 1    98.84%          24                 0   100.00%         196                 1    99.49%           0                 0         -
lightway-core/src/builder_predicates.rs                           20                10    50.00%           4                 2    50.00%          28                14    50.00%           0                 0         -
lightway-core/src/cipher.rs                                        8                 0   100.00%           3                 0   100.00%          13                 0   100.00%           0                 0         -
lightway-core/src/connection.rs                                  693               376    45.74%          56                21    62.50%         932               420    54.94%           0                 0         -
lightway-core/src/connection/builders.rs                          62                22    64.52%          21                 8    61.90%         268                60    77.61%           0                 0         -
lightway-core/src/connection/dplpmtud.rs                         761                90    88.17%          66                 1    98.48%         944                11    98.83%           0                 0         -
lightway-core/src/connection/fragment_map.rs                     132                11    91.67%          27                 0   100.00%         290                 7    97.59%           0                 0         -
lightway-core/src/connection/io_adapter.rs                       137                17    87.59%          36                 5    86.11%         313                23    92.65%           0                 0         -
lightway-core/src/connection/key_update.rs                        23                 7    69.57%           5                 0   100.00%          38                19    50.00%           0                 0         -
lightway-core/src/context.rs                                      90                25    72.22%          25                 7    72.00%         208                40    80.77%           0                 0         -
lightway-core/src/context/ip_pool.rs                               7                 3    57.14%           1                 0   100.00%           6                 0   100.00%           0                 0         -
lightway-core/src/context/server_auth.rs                          14                11    21.43%           4                 3    25.00%          24                20    16.67%           0                 0         -
lightway-core/src/encoding_request_states.rs                       2                 0   100.00%           1                 0   100.00%           3                 0   100.00%           0                 0         -
lightway-core/src/io.rs                                            3                 3     0.00%           3                 3     0.00%          10                10     0.00%           0                 0         -
lightway-core/src/lib.rs                                           9                 6    33.33%           4                 1    75.00%          18                 9    50.00%           0                 0         -
lightway-core/src/metrics.rs                                      15                15     0.00%          13                13     0.00%          29                29     0.00%           0                 0         -
lightway-core/src/packet.rs                                       27                 7    74.07%           4                 1    75.00%          30                 6    80.00%           0                 0         -
lightway-core/src/plugin.rs                                       66                 8    87.88%          23                 5    78.26%         160                 9    94.38%           0                 0         -
lightway-core/src/utils.rs                                       101                21    79.21%          22                 2    90.91%         184                17    90.76%           0                 0         -
lightway-core/src/version.rs                                      37                 0   100.00%          19                 0   100.00%          89                 0   100.00%           0                 0         -
lightway-core/src/wire.rs                                        156                27    82.69%          32                 0   100.00%         267                 6    97.75%           0                 0         -
lightway-core/src/wire/auth_failure.rs                             9                 1    88.89%           3                 0   100.00%          19                 0   100.00%           0                 0         -
lightway-core/src/wire/auth_request.rs                           147                12    91.84%          34                 0   100.00%         287                 0   100.00%           0                 0         -
lightway-core/src/wire/auth_success_with_config_ipv4.rs           69                 4    94.20%          13                 0   100.00%         145                 0   100.00%           0                 0         -
lightway-core/src/wire/data.rs                                    20                 1    95.00%           7                 0   100.00%          43                 0   100.00%           0                 0         -
lightway-core/src/wire/data_frag.rs                               41                 1    97.56%          17                 0   100.00%          92                 0   100.00%           0                 0         -
lightway-core/src/wire/encoding_request.rs                        24                 2    91.67%           6                 0   100.00%          46                 1    97.83%           0                 0         -
lightway-core/src/wire/encoding_response.rs                       24                 2    91.67%           6                 0   100.00%          46                 1    97.83%           0                 0         -
lightway-core/src/wire/ping.rs                                    22                 3    86.36%           7                 0   100.00%          68                 0   100.00%           0                 0         -
lightway-core/src/wire/pong.rs                                    15                 2    86.67%           5                 0   100.00%          34                 0   100.00%           0                 0         -
lightway-core/src/wire/server_config.rs                           20                 2    90.00%           5                 0   100.00%          44                 0   100.00%           0                 0         -
lightway-server/src/args.rs                                       27                27     0.00%          27                27     0.00%          27                27     0.00%           0                 0         -
lightway-server/src/auth.rs                                      104                36    65.38%          19                 5    73.68%         148                28    81.08%           0                 0         -
lightway-server/src/connection.rs                                 53                53     0.00%          24                24     0.00%         128               128     0.00%           0                 0         -
lightway-server/src/connection_manager.rs                        160               160     0.00%          40                40     0.00%         298               298     0.00%           0                 0         -
lightway-server/src/connection_manager/connection_map.rs          87                 9    89.66%          26                 2    92.31%         273                 9    96.70%           0                 0         -
lightway-server/src/io/inside/tun.rs                              25                25     0.00%           8                 8     0.00%          34                34     0.00%           0                 0         -
lightway-server/src/io/outside/tcp.rs                             83                83     0.00%          10                10     0.00%         108               108     0.00%           0                 0         -
lightway-server/src/io/outside/udp.rs                            145               145     0.00%          19                19     0.00%         267               267     0.00%           0                 0         -
lightway-server/src/io/outside/udp/cmsg.rs                        47                16    65.96%          14                 5    64.29%         237                56    76.37%           0                 0         -
lightway-server/src/ip_manager.rs                                 82                25    69.51%          19                 4    78.95%         254                28    88.98%           0                 0         -
lightway-server/src/ip_manager/ip_pool.rs                        101                 1    99.01%          32                 0   100.00%         303                 0   100.00%           0                 0         -
lightway-server/src/lib.rs                                       100               100     0.00%          12                12     0.00%         162               162     0.00%           0                 0         -
lightway-server/src/main.rs                                       81                81     0.00%          10                10     0.00%         215               215     0.00%           0                 0         -
lightway-server/src/metrics.rs                                    93                91     2.15%          82                80     2.44%         220               216     1.82%           0                 0         -
lightway-server/src/statistics.rs                                 53                23    56.60%           8                 4    50.00%         103                42    59.22%           0                 0         -
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL                                                           5371              2442    54.53%        1133               492    56.58%       10152              3709    63.47%           0                 0         -

✅ Region coverage 54% passes
✅ Line coverage 63% passes