Fixes players immediately being thrown out because the spawn teleportation triggered the PlayerLeaveListener
Reduces default velocity from the insane terminal velocity to just 1
Uses UUID instead of player object when storing dropper arena sessions
Prevents players from joining an arena if in creative, spectator mode, or is flying
Implements the leave command to allow leaving the arena
Only counts fall damage as a loss, but still prevents all damage in the arena
Prevents players from dying of fall damage when exiting the dropper arena
Prevents loadArenas from returning null
Removes some finished TODOs
Registers all listeners
Registers all commands
Adds more descriptive TODO comments to each command
Removes unintended double storage of dropper arena sessions in DropperArenaHandler
Adds methods for triggering a win, a loss and a quit
Calls the win, lose and quit methods as necessay in the listeners
Makes DropperArenaHandler store arena sessions and cleared stages
Moves code for keeping track of players to DropperArenaPlayerRegistry
Adds a DropperArenaRecordsRegistry for keeping track of records
Stores playing players as DropperArenaSession to be able to store more metadata
Adds an enum for different arena game-modes
Adds a record result enum for defining which kind of record a player achieved (personal or global)
Adds a helper-class for teleporting a player to and from arenas
