update ecl l1 and usage for new roll angle setpoint slew rate limit (#10005)

* added ability to slew rate limit the roll angle output of the l1 controller
* FixedWingPositionControl: this avoids the steps in roll angle setpoint which occur when the controller
switches to a new waypoint
* GroundRoverPositionControl: adapted to new l1 API

src/modules/fw_pos_control_l1/FixedwingPositionControl.hpp

@@ -306,6 +306,7 @@ private:
 		param_t l1_period;
 		param_t l1_damping;
 		param_t roll_limit;
+		param_t roll_slew_deg_sec;
 
 		param_t time_const;
 		param_t time_const_throt;