Marker interface for facilities.
Each interface that extends Facility provides an API over one particular feature that the application may want to control or observe.
Depending on the configuration and/or GroundSdk current state, some facilities may not be available.
Any facility, if available, can be obtained from a groundsdk session using:
groundsdk.getFacility(facilityClass)where facilityClass is the class of the facility interface to obtain.