add hypervisor server: ilo networking

[stuart-mclaren-hpe]

Add ilo networking stanza to server resource:

          ilo_network_info = {
                  ilo_ip = "16.182.105.216"
                  gateway = "16.182.104.1"
                  subnet_mask = "255.255.248.0"
          }

Note that naming is inconsistent, so we need to map between a list of this format in the POST /add-hypervisor-server http body:

        "iloMgmtIpInfo": {
          "ipAddress": "1.2.3.4",
          "subnetMask": "255.255.255.0",
          "gateway": "1.2.3.1"
        }

and this (non-list) format in the GET /server http response body:

  "iloNetworkInfo": {
    "iloIp": "1.2.3.4",
    "subnetMask": "255.255.255.0",
    "gateway": "1.2.3.1"
  },