move puzzle implementations out of engine

Assets/Engine/Runtime/Modules/State/ModuleState.cs

@@ -0,0 +1,21 @@
+using UnityEngine;
+
+namespace EscapeRoomEngine.Engine.Runtime.Modules.State
+{
+    /// <summary>
+    /// An abstract module state. Example implementations are <see cref="DoorState"/> and <see cref="PuzzleState"/>.
+    /// </summary>
+    [SelectionBase]
+    public abstract class ModuleState : MonoBehaviour
+    {
+        [Tooltip("The size of this module in meters.")]
+        public Vector2Int size = Vector2Int.one;
+        
+        public abstract void SetModule(Module module);
+
+        public override string ToString()
+        {
+            return name;
+        }
+    }
+}