Draft: Sync reservations using matrix
Current problems:
- Doesn't handle edits
- Doesn't handle deletions
- On both sides, one needs to go to the settings and select the room to use for syncing the tickets after each app restart
- On the receiving side, one needs to hit the sync button after each app restart; it will then keep syncing
- I'd massively prefer to limit this to encrypted rooms
- Not sure if the receiving side sends the thing right back to matrix, we might need to break a loop here