Creates config files out of cloud metadata

 os-apply-config apply configuration out of the cloud metadata (JSON) that it
 receives from a metadata server.
 .
 It turns metadata from one or more JSON files like this:
 .
  {"keystone":
   {"database":
    {"host": "127.0.0.1", "user": "keystone", "password": "foobar"}
   }
  }
 .
 into service config files like this:
 .
  [sql]
  connection = mysql://keystone:foobar@127.0.0.1/keystone