Add JEI Categories and related improvements

[WaitingIdly]

changes in this PR:

• adds the ability to add Categories to JEI.
• adds i18n wiki keys and update the examples file with the related compat.
• converts some JEI operations to be mixin-based, to ensure they happen after all other compat is run. without this, you are unable to remove catalysts from some categories or hide some ingredients.
• extracts the JEI information for InWorldCrafting into its own file.
• makes the documentation generation not generate the builder with comments on the wiki, even if commented is true.
• moves non-anto-generated files into a separate folder inside postInit.
• adds some examples for classes.
  • examples include a generic registry, bootleg reloading compat for the generic registry, and a IRecipeCategory used for the JEI category example (commented by default)
• adds a new custom groovy file to demonstrate the custom reloading compat.
  • this also demonstrates some event logic.