Add Center Function on Holes

Calculates the center of the hole.

demo/assets/scripts/environment/destructable/resource/hole.gd

@@ -8,3 +8,11 @@ var vectors: PackedVector2Array
 func _init(hole_id: int, vectors: PackedVector2Array):
 	self.hole_id = hole_id
 	self.vectors = vectors
+
+func center():
+	var avg_vert = Vector2.ZERO
+	
+	for v in vectors:
+		avg_vert += v
+	
+	return avg_vert / len(vectors)