Added back an example config for the Masa GUI.
Added back an example config for the Masa GUI.

Note: The ons-demo and Masa GUIs used to use the same config. The Masa GUI only
actually uses the 'cluster_basename' and 'controllers' fields. In the future
the GUI script should be refactored to not require all config parameters.

Change-Id: I3718536dbf12a71518204d3b2746c7afa4cae842

opennetworkinglab/spring-open,opennetworkinglab/spring-open,opennetworkinglab/spring-open,opennetworkinglab/spring-open,opennetworkinglab/spring-open,opennetworkinglab/spring-open