Rework landing gear logic

- remove deprecated actuator_controls[INDEX_LANDING_GEAR]
- remove dead code in mc rate controller that used to prevent it from being retracted
on the ground (anyway had no effect as it only affected the actuator_control[LANDING_GEAR]
which wasn't sent to the control allocation)
- for VTOLs handle deployment/retraction of landing gear in AUTO  as a MC (retract if
more than 2m above ground, deploy if WP is a landing WP), plus additionally when transition
flight task is called (ALTITUDE mode and higher)
- for FW in AUTO: add logic in FW Position Controller, depending on waypoint type mainly
- manual landing gear settings always come through (a manual command overrides a previous
auto command, and vice-versa)

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

src/modules/flight_mode_manager/tasks/Descend/FlightTaskDescend.cpp

@@ -36,6 +36,13 @@
 
 #include "FlightTaskDescend.hpp"
 
+bool FlightTaskDescend::activate(const trajectory_setpoint_s &last_setpoint)
+{
+	bool ret = FlightTask::activate(last_setpoint);
+	_gear.landing_gear = landing_gear_s::GEAR_DOWN;
+	return ret;
+}
+
 bool FlightTaskDescend::update()
 {
 	bool ret = FlightTask::update();

src/modules/flight_mode_manager/tasks/Descend/FlightTaskDescend.hpp

@@ -49,6 +49,7 @@ public:
 	virtual ~FlightTaskDescend() = default;
 
 	bool update() override;
+	bool activate(const trajectory_setpoint_s &last_setpoint) override;
 
 private:
 	Sticks _sticks{this};

src/modules/flight_mode_manager/tasks/Transition/FlightTaskTransition.cpp

@@ -57,7 +57,7 @@ bool FlightTaskTransition::updateInitialize()
 
 void FlightTaskTransition::updateParameters()
 {
-// check for parameter updates
+	// check for parameter updates
 	if (_parameter_update_sub.updated()) {
 		// clear update
 		parameter_update_s pupdate;
@@ -85,9 +85,19 @@ bool FlightTaskTransition::activate(const trajectory_setpoint_s &last_setpoint)
 
 	_velocity_setpoint(2) = _vel_z_filter.getState();
 
+	_sub_vehicle_status.update();
+
+	const bool is_vtol_front_transition = _sub_vehicle_status.get().in_transition_mode
+					      && _sub_vehicle_status.get().in_transition_to_fw;
+
+	if (is_vtol_front_transition) {
+		_gear.landing_gear = landing_gear_s::GEAR_UP;
+
+	} else {
+		_gear.landing_gear = landing_gear_s::GEAR_DOWN;
+	}
+
 	return ret;
-
-
 }
 
 bool FlightTaskTransition::update()

src/modules/flight_mode_manager/tasks/Transition/FlightTaskTransition.hpp

@@ -43,6 +43,7 @@
 #include <lib/mathlib/math/filter/AlphaFilter.hpp>
 #include <uORB/SubscriptionInterval.hpp>
 #include <uORB/topics/parameter_update.h>
+#include <uORB/topics/vehicle_status.h>
 #include <drivers/drv_hrt.h>
 
 using namespace time_literals;
@@ -63,6 +64,9 @@ private:
 	static constexpr float _vel_z_filter_time_const = 2.0f;
 
 	uORB::SubscriptionInterval _parameter_update_sub{ORB_ID(parameter_update), 1_s};
+
+	uORB::SubscriptionData<vehicle_status_s> _sub_vehicle_status{ORB_ID(vehicle_status)};
+
 	param_t _param_handle_pitch_cruise_degrees{PARAM_INVALID};
 	float _param_pitch_cruise_degrees{0.f};