[BACKLOG-218] Add event bus to the platform and make sure it is available on the DI Server
	- implemented async event bus leveraging on google-guava's
	- subscribers and events are wrapped in top level interfaces IMonitoringEvent and IMonitoringSubscriber
	- created a 'shell/skeleton' plugin whose only function is to startup MonitoringService
Merge pull request #1737 from pedrofvteixeira/monitoring

[BACKLOG-218] Add event bus to the platform and make sure it is available on the DI Server