lightware_laser: add option to listen to system to enable/disable distance sensor

msg/CMakeLists.txt

@@ -73,6 +73,7 @@ set(msg_files
 	DebugVect.msg
 	DifferentialPressure.msg
 	DistanceSensor.msg
+	DistanceSensorModeChangeRequest.msg
 	Ekf2Timestamps.msg
 	EscReport.msg
 	EscStatus.msg

msg/DistanceSensorModeChangeRequest.msg

@@ -0,0 +1,5 @@
+uint64 timestamp		# time since system start (microseconds)
+
+uint8 req_mode 			# requested mode of operation
+uint8 MODE_DISABLED = 0
+uint8 MODE_ENABLED  = 1