Huge update to AMBRA!

This update lays more of the foundation for a full-featured music player. Once the basic features are done, all the cool stuff can start making its way in.

All major changes:

- Added persistent, editable playlists with sidebar navigation
- Added play/shuffle (so far, there's more to come in the way of playing) for library and playlists
- Overhauled the library with separate pages for tracks, artists, and albums
- Improved search for better ranking and filtering
- Added playback restoration (being able to close the app and be in the same spot in the song)
- Added a super basic (and unstyled lol, pretty obviously no CSS) audio output switcher