Sync notes using the new sync framework

[provokateurin]

Depends on #21

[provokateurin]

While implementing most of #21 I realized that it doesn't make sense to implement this using the sync framework and it should be done with #543 instead.

[provokateurin]

Note: The sync framework should only be used for things that we don't control directly, like the users files or contacts or calendar events. We can't directly track changes to them unlike with user interaction inside our app, thus we need to have a framework that can manage to track changing states.