Weaken Golem Structure Requirements

[WaitingIdly]

changes in this PR:

• made is so the iron golem pattern applies '~', unused -> true instead of BlockWorldState.hasState(BlockMaterialMatcher.forMaterial(Material.AIR)), meaning any blocks will match it, not just AIR.
• made is so forming the iron golem will not replace the side bottom blocks [edit: whoops] or top side blocks.
• tied to a single config option. (default: false)

basically the same change as #464, but for Iron Golems.

[what-the-diff]

PR Summary

• Update to README.md
  The readme file has been updated to emphasize that the rigid requirements for building Iron Golems have been relaxed.

• Modification in UTConfigTweaks.java
  A new setting (utGolemPlacement) has been added to toggle the ability of creating Iron Golems. This aims to make Iron Golems' construction possible even when non-air blocks exist in the bottom corners of the base structure.

• Changes in UTLoadingPlugin.java
  Conditional logic (UTConfigTweaks.ENTITIES.utGolemPlacement) has been included which alters the application of certain modifications based on the configuration setting. This change determines when the newly introduced Iron Golem building rules should be applied.

• Introduction of UTGolemFormationMixin.java
  A new file has been added that modifies the way Iron Golems are formed and spawned. It allows for Golems to be created with non-air blocks in the lower corners of their structure.

• Addition of golemstructure.json
  This new JSON mixin file encapsulates modifications associated with the UTGolemFormationMixin class, allowing us to customize how Iron Golems are formed.