Implement the EmergencyStopController

The trigger_emergency_stop method should use the EmergencyStopMasterInterfacePrx to send an emergency stop.

Even though the init method is not defined in the design statement, you will still probably need it to create a new EmergencyStopMasterInterfacePrx.

Instantiate a new EmergencyStopController in the EmergencyStopService constructor and assign it to the attribute.