XaeroTracker

1. Add new config only-sync-same-world
2. Put the main logic to a dedicated thread
3. Use schedule enhanced throttle, ensuring that player's location will be accurate when player instantly stops after moving quickly

Add permission based tracking rule.

Player will no longer be displayed after being untracked (in previous versions, player's head will stay at origin until next time they are tracked)

Internationalize command feedback

1. Won't track players who are invisible(potion effect), in spectator mode or vanished(plugins such as super vanish)
2. Players can default choose not to be tracked
3. Ops can default choose to enable themselves to track everyone

create