add endpoint oper object

[jainvipin]

vendor in newer contivmodel
add oper object for an endpoint (show ip allocation, etc.)

[vagrant@netplugin-node1 netplugin]$ docker run -itd --net=junk --label=app=newapp alpine /bin/sh
efb4e447c3621169ad010558eeda474776ab62f16d41bc148ca8ae79d036fb4d

[vagrant@netplugin-node1 netplugin]$ netctl endpoint inspect efb4e
INFO[0000] Inspecting endpoint: efb4e                   
{
  "Oper": {
    "containerID": "efb4e447c3621169ad010558eeda474776ab62f16d41bc148ca8ae79d036fb4d",
    "homingHost": "netplugin-node1",
    "ipAddress": [
      "10.1.1.3",
      ""
    ],
    "labels": "map[app:newapp]",
    "macAddress": "02:02:0a:01:01:03",
    "name": "8c7e901c72dbe1eb2be496ed3727daf0de6008d88ac083b996784589cf059f2e",
    "network": "junk.default"
  }
}

[shaleman]

LGTM