Add editing of the genres list of the content

[Lorg0n]

This commit introduces the functionality for users to suggest changes to the genres of Anime, Manga, and Novel content types through the edit system. This enhances data accuracy by allowing the community to correct and update genre information.

Key changes include:

• Updated EditArgs schemas to accept a genres field, which is a list of genre slugs.
• Added validation in edit/dependencies.py to ensure all submitted genre slugs are valid before creating or updating an edit.
• Implemented the core logic in accept_pending_edit to correctly update the many-to-many relationship between the content and its genres.

[kuyugama]

I think, there's a better way to implement editing system(not modifying API). For example, separate validation for every distinct editable entity(anime, manga, novel, etc.). Also, make appliance of the edit the same way. This would make extending this system way more easier.

As for the genres, I think, this may work.