Some suggestions for extensions-lib

[Claudemirovsky]

1. • Season support
     Reason: It's annoying to do the separation of seasons manually, and bugs can easily appear in the implementation of some extensions.
     Theoretical implementation: A new property (season_number: Int, default: 0) could be added to the SEpisode model, and the episode list would be grouped according to season and episode number, maybe adding the season number as a prefix or something.
2. • Re-implementation of pagination in episodeList-related functions
     Reason: This was removed on this commit, and can help devs when fetching the episode list on sources that uses multiple pages. Currently we need to reinvent the wheel and create similar functions.
     Problem: This will surely break some extensions >:(
3. • Expose the Response.parseAs function
     Reason: It may be useful for JSON-API oriented extensions.
4. • Automatically generated documentation page
     Reason: This will be VERY useful for new and future contributors to aniyomi-extensions.
     Theoretical implementation: Maybe KDocs or something can help with that. Explaining better the functions exposed via extensions-lib and by adding usage examples, the documentation will be even clearer and will facilitate future extension development.