Beyond The End - Optimization and Fixes

Fix random Mutant More crash in common setup (brewing recipes)

The game sometimes failed to start with "Mutant More encountered an
error during the common_setup event phase:
ArrayIndexOutOfBoundsException: Index 16 out of bounds for length 15".

FMLCommonSetupEvent runs on several threads at once, and Mutant More
(like other mods) calls BrewingRecipeRegistry.addRecipe there without
enqueueWork. Forge keeps the recipes in a plain ArrayList, so two mods
adding a recipe at the same time corrupt it while it grows.

New mixin forge.BrewingRecipeRegistryThreadSafeMixin wraps the list
add in addRecipe(IBrewingRecipe) in a synchronized block on the list.
The other addRecipe overload delegates to this one, so every
registration is covered.