Use AndroidX DataStore

[OxygenCobalt]

Migrate from SharedPreferences to DataStore.

I'll likely get better performance and usability out of this. A funny technical quirk about Auxio is that I tried to serialize settings into integers, but in the end only made things even slower since it would just get shoved into an XML file IIRC.

DataStore has some kind of prototype buffer support, so I assume it's format is a lot better. Maybe it's listener management is also nicer.