- Introduce configurable storage mechanism
- LimboPersistence wraps a LimboPersistenceHandler, of which there are multiple implementations
- Outside of the limbo.persistence package, classes only talk to LimboPersistence
- Restore the way of persisting to JSON from 5.2 (SeparateFilePersistenceHandler)
- Add handling for stored limbo players
- Merge any existing LimboPlayers together with the goal of only keeping one version of a LimboPlayer: there is no way for a player to be online without triggering the creation of a LimboPlayer first, so we can guarantee that the in-memory LimboPlayer is the most up-to-date, i.e. when restoring limbo data we don't have to check against the disk.
- Create and delete LimboPlayers at the same time when LimboPlayers are added or removed from the in-memory map
- Catch all exceptions in LimboPersistence so a handler throwing an unexpected exception does not stop the limbo process (#1070)
- Extend debug command /authme debug limbo to show LimboPlayer information on disk, too
- Extract some logic into LimboServiceHelper to keep LimboService slim
- Create LimboServiceHelper#merge to merge two LimboPlayers associated with a Player. E.g. if an admin unregisters an online player that has not logged in, the creation of a LimboPlayer is triggered while there already is one in LimboService
