mavlink: use dynamic camera comp id instead of hardcoded value

msg/CMakeLists.txt

@@ -47,6 +47,7 @@ set(msg_files
 	baro_bias_estimate.msg
 	battery_status.msg
 	camera_capture.msg
+	camera_status.msg
 	camera_trigger.msg
 	cellular_status.msg
 	collision_constraints.msg

msg/camera_status.msg

@@ -0,0 +1,4 @@
+uint64 timestamp		# time since system start (microseconds)
+
+uint8 active_sys_id		# mavlink system id of the currently active camera
+uint8 active_comp_id 	# mavlink component id of currently active camera

msg/tools/uorb_rtps_message_ids.yaml

@@ -347,6 +347,8 @@ rtps:
     id: 161
   - msg: internal_combustion_engine_status
     id: 162
+  - msg: camera_status
+    id: 163
   ########## multi topics: begin ##########
   - msg: actuator_controls_0
     id: 180