Tiny Multiblock Lib

Unless I get more ideas, this might be the final major version. I'll try to avoid breaking changes from now on

• makeFullShape now has Level and its BE in its parameter
• Added a BlockEntity that's registered automatically, removing the need for custom BEs when not necessary
• Added Multiblock Structures, which are multiblocks with blocks underneath
• Added some helper utils for multiblock structures
• Moved most classes into common, meaning both loaders now have the same example blocks
• Expanding multiblock now reacts to block updates
• Fixed movable multiblock for the most part
• Added a Simple multiblock, a minimal implementation for mod devs to reference
• Renamed synced blockstates to shared blockstates, to avoid confusion
• Fixed a bug where previews used the wrong rendertype
• Fixed multiblocks breaking at world limit