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/Medical/Components/MedicalScannerComponent.cs

@@ -54,7 +54,7 @@ namespace Content.Server.Medical.Components
 
         public bool IsOccupied => _bodyContainer.ContainedEntity != null;
 
-        public override void Initialize()
+        protected override void Initialize()
         {
             base.Initialize();