admin guide updates for 3.5

[kaitlinnewson]

To do (from release notebook):

• app key
• scheduled tasks & jobs
  • update link to docs in config template (https://github.com/pkp/ojs/blob/stable-3_5_0/config.TEMPLATE.inc.php#L594) (PR: add link to docs for scheduled tasks ojs#5193)
• review config settings for any removals/changes
• altcha option
• reference to "ORCID plugin"
• Review users content with invitations in mind, and note config setting for expiration days

[kaitlinnewson]

Hi @touhidurabir, as part of updates to the administrator's guide for 3.5, I'm adding a page for scheduled tasks - would you mind reviewing the content in case I've missed anything important for this first version? We can always add more details later as well:

https://github.com/pkp/pkp-docs/pull/1349/files#diff-c16613b5b831fbe30f4fe70e4bb8b0e6c8bf7a14006570c21eba722e71ef2d33

[touhidurabir]

Hi @kaitlinnewson it look good .