Add storage nodes through GUI

[wimpers]

This ticket is a continuation of #378 and is to allow to add storage nodes through GUI:

• re-introducing the ADD button on the ALBA backend page which asks for IP, Login, Passwd, chassis type
• looping over the different disks and adding the detected OSDs to the DB
• allowing to claim the disks (initialize isn't required?)
• decommission an OSD

[wimpers]

Keep this on hold as we don't have specs of the chassis yet.

[JeffreyDevloo]

Would this remove the need of discovering asd-manager nodes?

[wimpers]

I would keep the discovery we have right now, unless there is a good reason to remove it.

[kvanhijf]

@wimpers : Whats the status of those required specs?

[wimpers]

Still waiting for specs alas .. I'll keep it assigned to myself

[wimpers]

API can be found at http://172.16.0.63/
Specs at https://drive.google.com/open?id=1-4pcPXkRY62pV0r4_x2iu_uAF5XRfIKW

curl 'http://172.16.0.63/api.php/slots/1' | jq
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   531    0   531    0     0   4382      0 --:--:-- --:--:-- --:--:--  4388
{
  "success": true,
  "results": {
    "location": 1,
    "present": false,
    "worldwidename": "",
    "last_seen": 571623.7818799,
    "powered_on": false,
    "network_interfaces": [
      {
        "ipv4_address": "",
        "ipv6_address": "",
        "mac_address": ""
      },
      {
        "ipv4_address": "",
        "ipv6_address": "",
        "mac_address": ""
      }
    ],
    "temperature": null
  }
}