Add initial resource and presenter classes for game entities and effects

Code/Presenters/EntityPresenter.cs

@@ -0,0 +1,11 @@
+using GameCore.ECS;
+using GameCore.ECS.Interfaces;
+using Godot;
+
+namespace CryptonymThunder.Code.Presenters;
+
+[GlobalClass]
+public partial class EntityPresenter : Node3D, IEntityPresenter
+{
+    public Entity CoreEntity { get; set; }
+}