Add test directory for command localize

Create simple kustomization directory that `kustomize localize` can download as remote reference in test.

api/krusty/testdata/localize/simple/service.yaml

@@ -0,0 +1,11 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: test-service-simple
+spec:
+  selector:
+    app: deployment-simple
+  ports:
+    - protocol: TCP
+      port: 80
+      targetPort: 8080