Added GameObject Validators

Editor/Validators/GameObject/GameObjectValidatorBrokenPrefab.cs

@@ -0,0 +1,15 @@
+using System.Collections.Generic;
+using UnityEditor;
+using UnityEngine;
+
+namespace Module.ProjectValidator.Editor
+{
+    internal sealed class GameObjectValidatorBrokenPrefab : IGameObjectValidator
+    {
+        public void Validate(GameObject gameObject, List<ValidatorResult> results)
+        {
+            if (PrefabUtility.IsPrefabAssetMissing(gameObject))
+                results.Add(ValidatorResult.Create(EValidatorSeverity.Error, "GameObject is missing prefab asset"));
+        }
+    }
+}