Enable DO_SET_SPEED commands outside of missions in other AUTO modes (#18834)

* Navigator: enable DO_CHANGE_SPEED for outside of mission
- update _mission_cruising_speed_mc/_fw also if DO_CHANGE_SPEED command
is received outside of mission (e.g. while Loitering doing an Orbit)
- if vehicle is in AUTO_LOITER when receiving the change speed, then immediately
apply it by doing a reposition without updating any other field than cruising_speed
and cruising_throttle
-when RTL is activated reset the cruising speed and throttle

* Navigator: reset cruise speed and throttle to default when VTOL-transitioning

Signed-off-by: Silvan Fuhrer <silvan@auterion.com>

src/modules/navigator/rtl.cpp

@@ -287,6 +287,10 @@ void RTL::on_activation()
 
 	setClimbAndReturnDone(_rtl_state > RTL_STATE_RETURN);
 
+	// reset cruising speed and throttle to default for RTL
+	_navigator->set_cruising_speed();
+	_navigator->set_cruising_throttle();
+
 	set_rtl_item();
 
 }