fixed-wing runway takeoff: climbout at specified takeoff airspeed and max climb rate

TECS climbout mode was used for takeoff climbout, which puts throttle to full and does not regulate a specific airspeed.
This commit sets the desired takeoff airspeed explicitly and allows max climb rate to track the ascent.

src/modules/fw_pos_control_l1/FixedwingPositionControl.hpp

@@ -698,12 +698,14 @@ private:
 	 * @param climbout_mode True if TECS should engage climbout mode
 	 * @param climbout_pitch_min_rad Minimum pitch angle command in climbout mode [rad]
 	 * @param desired_max_sink_rate The desired max sink rate commandable when altitude errors are large [m/s]
+	 * @param desired_max_climb_rate The desired max climb rate commandable when altitude errors are large [m/s]
 	 * @param disable_underspeed_detection True if underspeed detection should be disabled
 	 * @param hgt_rate_sp Height rate setpoint [m/s]
 	 */
 	void tecs_update_pitch_throttle(const float control_interval, float alt_sp, float airspeed_sp, float pitch_min_rad,
-					float pitch_max_rad, float throttle_min, float throttle_max, bool climbout_mode, float climbout_pitch_min_rad,
-					const float desired_max_sink_rate, bool disable_underspeed_detection = false, float hgt_rate_sp = NAN);
+					float pitch_max_rad, float throttle_min, float throttle_max, bool climbout_mode,
+					float climbout_pitch_min_rad, const float desired_max_sink_rate, const float desired_max_climb_rate,
+					bool disable_underspeed_detection = false, float hgt_rate_sp = NAN);
 
 	/**
 	 * @brief Constrains the roll angle setpoint near ground to avoid wingtip strike.