Add yaml files for user mongo service

gcloud/user-mongo/user-mongo-deployment.yaml

+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: user-mongo
+spec:
+  selector:
+    matchLabels:
+      app: user-mongo
+  replicas: 1
+  template:
+    metadata:
+      labels:
+        app: user-mongo
+    spec:
+      containers:
+        - name: user-mongo
+          image: mongo
+          ports:
+            - containerPort: 27017
+          volumeMounts:
+            - name: mongo-data
+              mountPath: /data/db
+      volumes:
+        - name: mongo-data
+          persistentVolumeClaim:
+            claimName: user-mongo-volume
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: user-mongo-service
+spec:
+  selector:
+    app: user-mongo
+  ports:
+    - name: mongo-port
+      protocol: TCP
+      port: 27018
+      targetPort: 27017
+  type: ClusterIP

gcloud/user-mongo/user-mongo-pvc.yaml

+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: user-mongo-volume
+spec:
+  storageClassName: default-mongo
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 1Gi