Chore: Audiobookshelf: Less API calls + more debugging messages

[fmunkes]

Improvements

API calls [commits on Jan 21st/ 22nd]

API calls are reduced significantly by

• making use of the minimized versions of podcast/ audiobooks provided to us anyways when syncing library items. Just a single api call per library, instead of several per item.
• storing the libray items ids in the client instead of acquiring them in browse function

Schema [commits today]

• If schema parsing fails, this is logged as an error now.
• I commented as many attributes as possible in abs_schema.py, which we don't use currently. No blaming intended, but I think the API docs of abs are not completely up to date with development, thus my typing is apparently not always appropriate.
  Nonetheless, I'll see how can do snapshot testing this weekend.

Other

• There is a 1s delay before returning session details. I sometimes had the issue of mass being faster in acquiring than abs in creating the stream
• Discord: There is an advanced option in the setup screen, which won't sync podcasts with no episode.