Qurt qshell implementation (#20736)

msg/CMakeLists.txt

@@ -145,6 +145,8 @@ set(msg_files
 	PpsCapture.msg
 	PwmInput.msg
 	Px4ioStatus.msg
+	QshellReq.msg
+	QshellRetval.msg
 	RadioStatus.msg
 	RateCtrlStatus.msg
 	RcChannels.msg

msg/QshellReq.msg

@@ -0,0 +1,5 @@
+uint64 timestamp		# time since system start (microseconds)
+char[100] cmd
+uint32 MAX_STRLEN = 100
+uint32 strlen
+uint32 request_sequence

msg/QshellRetval.msg

@@ -0,0 +1,3 @@
+uint64 timestamp		# time since system start (microseconds)
+int32 return_value
+uint32 return_sequence