Improved caching, performance, and database calls

Flats are now stored case-insensitive

• A flat called hello is now treated the same as HELLO
• All existing flats are migrated automatically, appending a _dupX suffix to duplicates

/flats show no longer uses blocks to mark flats

• Uses BlockDisplays instead

Further improved update-command functionality

• Updates will now be applied automatically on server restart by taking advantage of Papers update directory

Improved caching with Caffeine

Better tab completion when using /flats untrust