Support sqlite paper managers

[j6k4m8]

This should also optionally track all edits (as diffs) for debugging.

[wrongu]

Is this not already available as git history?

[j6k4m8]

Sure, but poorly-defined to get out tuples of (edit request, before, after) and also requires pulling the full git history into memory which is annoying and slow...

[j6k4m8]

^

• also overleaf rewrites its history all the time because it's not actually a git history
• also also this would handle paper pointer management, not just edit tracking

[wrongu]

while you're at it, you should turn PaperRemote.dict() into an actual class specification, and generalize the loading in the managers