Simplify and improve mixins

[BluSpring]

• Heavily improves and simplifies mixins by avoiding @Overwrite and @Redirect calls where possible, which also helps with mod compatibility
• Adds MixinSquared to cancel Veil's AO mixin, allowing the mod to still reapply Veil's "Disable Ambient Occlusion" without reimplementing the entirety of Indigo's AO handling
• Remove a bunch of mods from the breaks list
  • This can be reverted if needed.

[HerrChaos]

is there a reason you removed mods from the incompatibility list?

[BluSpring]

Due to the extensive changes to the mixins, the mods in question have a high likelihood of actually working with this. But I still haven't gotten around to properly testing if they do in fact work - hence why I mention that it can be reverted.

The mods that I am aware that break:

• OptiFine
• Sodium (and subsequently Iris)
  • A crash that does occur with LWJGL/GLFW here is caused by the WindowMixin setting the debug context, btw, if you ever feel like making Sodium work. Veil is still not updated to work with newer versions of Sodium.

[SpacePotatoee]

The reason those mods are incompatible is because of Veil not being compatible with other renderers. Not sure if the mixins had anything to do with that