Implement keystone v2 auth feature in mq

## Implement keystone v2 auth feature in mq

You should add 4 wrapped fields to your iron.json:

```
{
  "project_id": "...",
  "keystone": {
    "username": "...",
    "password": "...",
    "server": "...",
    "tenant": "...",
  }   
}
```

Look at `testUseKeystone()` test if you want to perform keystone auth programmatically.