feat: IAssignableGameObject to ITransform

I originally didn't want ITransform to have a reference to any IGameObject, since it didn't seem necessary to couple these two, and to make ITransform more flexible and reusable but without it we can't get a reference to the IGameObject(s) that's using that ITransform without doing some very stupid workarounds. I'll try to find a better way for this.

Engine.Core/Factory/GameObjectFactory.cs

@@ -22,6 +22,9 @@ public class GameObjectFactory
         behaviourController ??= TypeFactory.Get<BehaviourController>();
         stateEnable ??= TypeFactory.Get<StateEnable>();
 
+        if (!transform.Assign(gameObject))
+            throw AssignException.From(transform, gameObject);
+
         if (!behaviourController.Assign(gameObject))
             throw AssignException.From(behaviourController, gameObject);
         if (!stateEnable.Assign(gameObject))