WIP: Floodgate-Fabric merge

[onebeastchris]

This is a work-in-progress PR. While i think this might be a good start, this still has quite a long way to go.

Changes made/needed:

• Tried to split up the fabric code into fabric-platform specific code & "mod-common" code. Not yet needed, but should help with making a forge port
• Updated gradle to 8.4
• added architectury

TODOs:

• [x] Fix building
• [ ] Re-add h2 dependency when architectury updates
• [ ] Add modrinth publishing
• [ ] NeoForge support - depends on architecture support for neo, cloud for neo, etc
• [ ] Dependency configuration
• [ ] Testing
• [ ] Backport naming fix (https://github.com/GeyserMC/Floodgate-Fabric/commit/1900da2ff00a8dccfcd498c00cac5a44f9839b85)
• [ ] Mixin configuration
• [ ] Universal module

and probably a few dozen other things :p