Engine Entity Anchoring Changes (#4195)

* Converted all SnapGridPositionChangedEvent subscriptions to AnchorStateChangedEvent.

* Fixes power tests with new anchored requirements.

* Moved AnchorableComponent into construction.
AnchorableComponent now uses Transform.Anchored.

* Fixed bug with nodes, power works again.

* Adds lifetime stages to Component.

* Update Engine to v0.4.70.

Content.Server/Power/Components/PowerReceiverComponent.cs

@@ -92,7 +92,7 @@ namespace Content.Server.Power.Components
             }
         }
 
-        public override void OnRemove()
+        protected override void OnRemove()
         {
             _provider.RemoveReceiver(this);
             base.OnRemove();