Seperate the project into better structure

[dayeya]

If it isn't intentional, separating the project into separate folders may be the best for readability, easier navigation, and maintainability.

[elesiuta]

I've been considering this for the past few releases. Originally a single file made it easier to distribute and run for less experienced users, but now it's grown to the point where it probably makes sense to split up, and I've now packaged it for most distros.

I also don't see picosnitch growing much larger, at least from my end since it has all the features I planned, with only minor changes from bug fixes or dependency updates remaining (I am open to pull requests with new features).

I have a local branch where I started working on this, and may just push as is later, but I don't have much experience with packaging, specifically the rpm and nix packages look like they'll break and will take some work since I'm not setup to build and test them right now.

A single file also made it simpler to re-execute as root or daemonize itself on systems without systemd, and since I don't spend much time on this anymore, I'm hesitant to make any breaking changes until someone who's made a few contributions wants to take over maintenance or volunteers to test and fix it on multiple distros.

For now there is a callgraph in the docs folder which can help with navigating the code.

[elesiuta]

I pushed the branch here https://github.com/elesiuta/picosnitch/tree/split-file where I just split the script into a module with no other changes or fixes for packaging, systemd, daemonizing, etc, and needs to be run with sudo python3 -m picosnitch

At this point it's basically just for interest and unlikely anything will come from it anytime soon.