Add new library category for album artist

[secure-username]

There is already a library category for artist, but I believe album artist is more useful, and wouldn't include a bunch of extra artists from things like soundtracks or compilation albums.

Actual behaviour

• There is no library category for album artist.

Expected behaviour

• Either album artist is added as a new category or replaces the artist category.

Steps to reproduce

1. Open app
2. View library categories
3. Be sad

Environment data

Android version: 10

Device model: Onepolus 7 Pro

Stock or customized system: LineageOS

Music-Player app version: 1.3.3