Templates 2

Old changes (~2023, unreleased until now):

• Start sketching out an API, accessible through TemplatesClientApi.getInstance()
  • (Note from the future: This API will break hard in 1.21 due to Mojang fuckery)
• Code cleanups that hopefully didn't break ABI compat
• Remove some unused stuff from the jar
• Vertical slab placement is a little better
• Fix a bug where templates that look like blocks with randomized models, such as stone, could reroll their blockstate on every resource load
  • Forgot to specify a random seed.
  • Templated blocks always use the same model -- templated stone will still not be randomly rotated/flipped -- but at least now it uses the same same model.

New changes:

• New template: "Post Cross" - a plus shape that fits squarely on fences or the Post template. Can be placed in three different orientations.
• New template: "TNTemplate". This will end well.
• Connected textures should work! I tested with Chisel Reborn. Other blocks should be OK as long as they implement FabricBlock#getAppearance.
• Mushroom blocks now work (as well as any other blocks with "multipart" models).
• Very slightly reduce memory usage of TemplateAppearance?
• Only declare dependencies on the Fabric API modules I actually use.

TODO list:

• I still depend on two deprecated modules, fabric-rendering-data-attachment-v1 (has ABI implications) and fabric-models-v0 (the replacement seems to be fabric-model-loading-api-v1, and this also has ABI implications)