Preflight surface checks on PX4

Dear team,

I thought it would be handy to be able to check the functionality and configuration of the control surfaces in preflight checklist. Motor test sliders in QGC are not self explanotary for the moving surfaces as it is for ESCs. For example, what should it be seen when left servo of A-tail is slid to top? But, I know what I need to observe when I send yaw left, pitch down, or any other configuration command. Instead of sliding them individually, we should be able to send rolling, pitching, and yawing commands and see the corresponding servo movements depending on the airframe. By this way, we achieve an airframe-independent global checklist.