flightgear hil: correct scaling of pressure for mavlink message and remove indicated airspeed from flightgear protocol, commit requires flightgear protocol update

Fixed race issues in config upload, tested to be reliable now - board startup scripts now need the other half of testing

Instantiate a PX4 config view in PX4 mode from start, since boards with just the bootloader (or no working telemetry) cannot be flashed else.

Checkpoint: RC calibration much better / operation, can use UI tweaks. Airframe config in, but not operational and still very functional / ugly.

Implementation of Battery Monitor configuration, and addition of AP2ConfigWidget, which automatically handles UAS connections to allow for simpler configuration window code.