Add CephObjectStoreUser for Postgres backup

applications/templates/cloudnativepg.yaml

@@ -68,3 +68,17 @@ spec:
   storage:
     size: 50Gi
     storageClass: local-path
+---
+apiVersion: ceph.rook.io/v1
+kind: CephObjectStoreUser
+metadata:
+  name: postgres-backup-user
+  namespace: rook-ceph
+spec:
+  store: rgw-bulk
+  displayName: "Postgres Backup User"
+  quotas:
+    maxSize: 400G
+  capabilities:
+    user: "*"
+    bucket: "*"