Fix Antimatter engine maths and overplacing (#2736)

* Antimatter engine parts can't be placed overlapping

* Antimatter engine stability maths fixed

* Antimatter engine: Clean up some unused stuff

Content.Server/GameObjects/Components/Power/AME/AMEShieldComponent.cs

@@ -26,11 +26,6 @@ namespace Content.Server.GameObjects.Components.Power.AME
             Owner.TryGetComponent(out _pointLight);
         }
 
-        internal void OnUpdate(float frameTime)
-        {
-            throw new NotImplementedException();
-        }
-
         public void SetCore()
         {
             if(_isCore) { return; }