Introduce Comparator interface (#88016)

* Introduce Comparator interface

* Add compare implementation everywhere

* Add comment explaining what Compare should do

* Lint

pkg/registry/apis/service/storage.go

@@ -60,3 +60,9 @@ func newStorage(scheme *runtime.Scheme, optsGetter generic.RESTOptionsGetter) (*
 	}
 	return &storage{Store: store}, nil
 }
+
+// Compare asserts on the equality of objects returned from both stores	(object storage and legacy storage)
+func (s *storage) Compare(storageObj, legacyObj runtime.Object) bool {
+	//TODO: define the comparison logic between a generic object returned by the storage and a generic object returned by the legacy storage
+	return false
+}