Better MC Skyblock [BMCS]

[Mutated Items Update]

- Added Mutated Items (by Furti_Two)
- Added Mutated Items Quests & a few more Quests
- Made Cattail Sprout Compostable
- Improved how server thread is ensured in singleplayer, fixing many real and potential issues
- Fixed frostwalk protection race condition crash in singleplayer
- Fixed race condition crash when fixing inconsistencies in party data
- Fixed many real and potential issues in singleplayer by adding a lot of ServerLevel null checks
- Fixed players sometimes getting stuck online
- Fixed presents not working
- Bountiful Fixes

AS ALWAYS BACKUP YOUR WORLD BEFORE UPDATING