sensors: move mag aggregation to new VehicleMagnetometer WorkItem

- purge all reminaing magnetometer IOCTL usage
 - mag calibration add off diagonal (soft iron) scale factors

msg/tools/uorb_rtps_message_ids.yaml

@@ -158,7 +158,7 @@ rtps:
     id: 67
   - msg: sensor_mag
     id: 68
-  - msg: sensor_preflight
+  - msg: sensor_preflight_imu
     id: 69
   - msg: sensor_selection
     id: 70
@@ -297,6 +297,8 @@ rtps:
     id: 132
   - msg: telemetry_heartbeat
     id: 133
+  - msg: sensor_preflight_mag
+    id: 134
   ########## multi topics: begin ##########
   - msg: actuator_controls_0
     id: 150