Fixed possible deadlock during tree gen. Bunch more fixes.

Fixes #1306, #1307, #1313

* Fixed GameMode command not parsing correctly.
* Fixed Cauldron debug logging.
* Added entity removal for entities with invalid locations during chunk load.
* Added new config option 'entities.skip-ticks-near-unloaded-chunks' which is disabled by default.
- If set to false, it can help with performance at the expense of entity wandering into unloaded chunks and moveable chunkloaders.
* Moved config option 'world-settings.default.despawn-immediate' to 'world-settings.default.entities.despawn-immediate'
* Catch invalid chunkpositions during Stronghold gen
* Cleaned up some code