Merge pull request #24751 from krousey/meta_unstructured

Automatic merge from submit-queue

Redo Unstructured to have accessor methods

Add accessor methods that implement pkg/api/unversioned.ObjectKind,
pkg/api/meta.Object, pkg/api/meta.Type and pkg/api/meta.List.

Removed the convenience fields since writing to them was not reflected
in serialized JSON.

pkg/api/meta/interfaces.go

@@ -177,3 +177,5 @@ type RESTMapper interface {
 	AliasesForResource(resource string) ([]string, bool)
 	ResourceSingularizer(resource string) (singular string, err error)
 }
+
+var _ Object = &runtime.Unstructured{}