Add some ecs todo's

libs/ecs/include/psemek/ecs/container.hpp

@@ -20,8 +20,11 @@ namespace psemek::ecs
 
 	// TODO:
 	// - Fully document which functions can be called from which callbacks
-	// - Constructors & destructors implementation
-	// - Modification callbacks implementation
+	// - Constructors & destructors implementation (const-only)
+	// - Modification callbacks implementation (const-only)
+	// - Entity cloning
+	// - Registering components
+	// - Tables serialization
 	// - Refactor query caches
 	// - Index API
 	// - Index implementation