Render the service_net_map to fall back to the ctlplane network when
networks are disabled (or not defined) in network_data.yaml.
Also use startswith for Ceph roles which should all have 'storage'
as the HostnameResolveNetwork.
Closes-Bug: #1809313
Change-Id: I737d5656b113f7e2238fe7bb555cc2d4cb13877c