Add emergencyBell as option to EquipmentTypes

[k00ni]

This would allow EquipmentInfo and -Properties to be used for emergency bell modelling.

[opyh]

Thanks! We also thought about this as we found some datasets containing this.

#30 contains this as extra EmergencyDevice model for now. This is now modeled from a user’s/guest’s/tenant’s perspective rather than a manufacturer’s or facility manager’s.

For more fancy use cases like IoT emergency facility management, I’d rather rely on work bodies like http://iotschema.org/docs/full.html and similar projects as an implementor.