NeoForge 1.21.1-6.3.0.0-NEOFORGE

Changelog Version 1.21.1-6.3.0.0

Multiloader Release. NeoForge and Fabric! 1.21.1-6.3.0.0
Rename to interface class to start with I
Add REI plugin. Only show modpack book conditionally.
Add loot modifiers for Fabric so Fiber and sticks drop. Bonus rant about the Fabric implementation being stupid.
Move JEI plugin to common so it is available in Fabric.
Match load order in Fabric.
Add back flint knapping with vanilla flint item. People can't read.
Update registration order so Blocks are loaded before BlockItems. Babric is too dumb.
Don't load NeoForge specific data on Fabric.
Multiloader datagen.
Update Handbook version.
Cleanup.
Rename sounds class to something not generic.
Update event handlers.
Add platform libaries.
Remove old book resources. Add generated book data.
Migrate events to common. Add Fabric events.
Initial multiloader port.
Relocate for multiloader setup.
Update README