timesync: extend timesync_status message with protocol source field and enum

msg/timesync_status.msg

@@ -1,5 +1,10 @@
-uint64 timestamp		# time since system start (microseconds)
+uint64 timestamp			# time since system start (microseconds)
+
+uint8 SOURCE_PROTOCOL_MAVLINK = 0
+uint8 SOURCE_PROTOCOL_RTPS = 1
+uint8 source_protocol			# timesync source. Source can be MAVLink or the microRTPS bridge
+
 uint64 remote_timestamp		# remote system timestamp (microseconds)
-int64 observed_offset		# raw time offset directly observed from this timesync packet (microseconds)
-int64 estimated_offset		# smoothed time offset between companion system and PX4 (microseconds)
-uint32 round_trip_time		# round trip time of this timesync packet (microseconds)
+int64 observed_offset			# raw time offset directly observed from this timesync packet (microseconds)
+int64 estimated_offset			# smoothed time offset between companion system and PX4 (microseconds)
+uint32 round_trip_time			# round trip time of this timesync packet (microseconds)

src/modules/mavlink/mavlink_timesync.cpp

@@ -141,6 +141,7 @@ MavlinkTimesync::handle_message(const mavlink_message_t *msg)
 				timesync_status_s tsync_status{};
 
 				tsync_status.timestamp = hrt_absolute_time();
+				tsync_status.source_protocol = timesync_status_s::SOURCE_PROTOCOL_MAVLINK;
 				tsync_status.remote_timestamp = tsync.tc1 / 1000ULL;
 				tsync_status.observed_offset = offset_us;
 				tsync_status.estimated_offset = (int64_t)_time_offset;