Remove some redundant "elevon" stuff for now. Will come back later when proper "elevon + rudder" artwork exists. Currently no different from vtail anyway...

Enabled proper channel mixing settings inside the FixedWing wizard Output configuration screen. Attempt to set GUIConfigDataUnion to fixedwing
Sort out issues with servo vs. motor sliders... finally figure out what wizardIndexes are! per OutputCalibrationPage::setWizardPage()