rover: add rover-specific position setpoint

msg/CMakeLists.txt

@@ -174,6 +174,7 @@ set(msg_files
 	RcParameterMap.msg
 	RoverAttitudeSetpoint.msg
 	RoverAttitudeStatus.msg
+	RoverPositionSetpoint.msg
 	RoverRateSetpoint.msg
 	RoverRateStatus.msg
 	RoverSteeringSetpoint.msg

msg/RoverPositionSetpoint.msg

@@ -0,0 +1,6 @@
+uint64 timestamp # time since system start (microseconds)
+
+float32[2] position_ned # 2-dimensional position setpoint in NED frame [m]
+float32 cruising_speed  # (Optional) Specify rover speed (Defaults to maximum speed)
+
+float32 yaw             # [rad] [-pi,pi] from North. Optional, NAN if not set. Mecanum only.