Audiobook support phase 1: DB representation

[aaronleopold]

In an effort to avoid major breaking changes down the road, I'll plan to add DB-level support for audiobooks alongside #196. For context as to why or how this makes sense, read this comment: https://github.com/stumpapp/stump/issues/196#issuecomment-1902759400

[applesoff]

This is probably a little early on. But if you add audiobooks and epubs together, there is a FOSS program called Storyteller that can overlay the two. Similar to Amazon's whisper sync. That would be a nice addition

[aaronleopold]

I'll look into it a bit closer to when this will be worked, sounds neat - thanks! I assume you mean this

[applesoff]

That is correct