Rigify To Unity Function

- This is an work in progress, this expands on the system that NyankoNyan and improves that system.

- It remaps the bone hierarchy to match Unity's expectations
- It adds necessary constraints to ensure proper bone movement (For the people who need it, can be removed via remove constraints button).
- It removes redundant bones that could cause issues in Unity.
- It renames bones to match Unity's Humanoid Avatar naming convention.
- It provides an option to merge or remove twist bones, which are not supported by Unity's humanoid system.
- It adjusts bone connections and deformation settings.

I think more needs to be added, but this seems to work for now.

core/properties.py

@@ -63,6 +63,11 @@ def register() -> None:
         min=0.0,
         max=2.0
     )))
+    register_property((bpy.types.Scene, "merge_twist_bones", bpy.props.BoolProperty(
+        name=t("Tools.merge_twist_bones.label"),
+        description=t("Tools.merge_twist_bones.desc"),
+        default=True
+    )))
 
     register_property((bpy.types.Scene, "selected_armature", bpy.props.EnumProperty(
         items=get_armatures,