Features:
- Move Loader's runtime transformers to the transform cache [#352]
  - This gives us a chance to dogfood the transform cache in more situations and may slightly reduce load times.
  - With this change, we are starting the process of requiring Class Path Groups to be properly configured by every mod.
    See the [template mod](https://github.com/QuiltMC/quilt-template-mod/blob/1.20.1/build.gradle#L21) for more information.

Bug Fixes:
-  [#356] Transform cache no longer regenerates each launch
- [#366] Fix backwards compatibility issue where mods incorrectly using the fabric loader internal class "EntrypointUtils" didn't throw the same exception type in quilt.
- [#367] Parse pre-1.6 arguments
- Quiet overzealous logging when using split source sets

