[ Autonomic ] Create a Decanter collector for Roboconf

[vincent-zurczak]

We can already use Decanter to monitor Roboconf itself (DM and agents).
We could also use it to monitor applications that are managed by agents. Therefore, we would need to write our own Decanter collector.

This one could be used with all the appenders Decanter has (e.g. the Elastic Search one). We would then be able to create dashboards that include both the monitoring of Roboconf and the monitoring of running applications.