ekf2: separate mag and mag heading control logic (#21212)

- split mag_3d into new standalone mag fusion and mag fusion allowed to update all states (full mag_3d)
 - new dedicated control logic for mag/mag_3d fusion and standalone mag heading fusion
 - if WMM available use for mag_I and mag_B init
 - mag states reset if external yaw reset (yaw estimator, GPS yaw, etc)
 - mag reset if declination changed (eliminate _mag_yaw_reset_req)
 - mag fusion (but not mag_hdg or mag_3d) can be active during gps_yaw or ev_yaw (if yaw aligned north)

Co-authored-by: bresch <brescianimathieu@gmail.com>

src/modules/ekf2/EKF/zero_velocity_update.cpp

@@ -46,7 +46,7 @@ void Ekf::controlZeroVelocityUpdate()
 	if (zero_velocity_update_data_ready) {
 		const bool continuing_conditions_passing = _control_status.flags.vehicle_at_rest
 				&& _control_status_prev.flags.vehicle_at_rest
-				&& !isVerticalVelocityAidingActive(); // otherwise the filter is "too rigid" to follow a position drift
+				&& (!isVerticalVelocityAidingActive() || !_control_status.flags.tilt_align); // otherwise the filter is "too rigid" to follow a position drift
 
 		if (continuing_conditions_passing) {
 			Vector3f vel_obs{0, 0, 0};