Add Coming Soon to NYI PX4 vehicle config screens.

This should remove some of the confusion around this. They now say Coming Soon and point you to either Advanced Config or Radio Calibration as appropriate.

Also remove APM code from PX4 Vehicle Config side. PX4 Vehicle Config looks like it was originally copied from the APM QGCVehicleConfig code. Pulled out the code which is never reached due to the APM widget files not being found.