Add yaml files for user service deployment

gcloud/user-service/user-service-autoscaler.yaml

+apiVersion: autoscaling/v1
+kind: HorizontalPodAutoscaler
+metadata:
+  name: user-service-hpa
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: user-service
+  minReplicas: 1
+  maxReplicas: 5
+  targetCPUUtilizationPercentage: 80

gcloud/user-service/user-service-deployment.yaml

+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: user-service
+spec:
+  selector:
+    matchLabels:
+      app: user-service
+  replicas: 3
+  template:
+    metadata:
+      labels:
+        app: user-service
+    spec:
+      containers:
+        - name: user-service
+          image: europe-west2-docker.pkg.dev/daily-384822/daily-repo/user-service:v1
+          ports:
+            - containerPort: 9000
+          env:
+            - name: MONGO_URI
+              value: "mongodb://user-mongo-service:27018/userdb"
+            - name: ENABLE_USER_DB_SEEDING
+              value: "true"