NavigationWizard: do not inherit from VehicleConfigurationSource

The VehicleConfigurationSource has a bunch of pure virtual functions
that make sense for a general SetupWizard but not for specific aspects
like navigation.  So the navigation wizard does not inherit from it
anymore.

The SetupWizard functions using this should be moved _into_ the
VehicleConfigurationSource and it should forward calls (or let
the pages directly access its VehicleConfigurationSource object).
AbstractWizard: add getQWizard getObjectManager methods

The getQWizard is based on the previous commit comments.  Make a method
to get the minimal interface required to establish a better abstraction
from wizard methods and configuration methods.

The getObjectManager helps for direct access to objects.  For consistency
with the current implementation it should be used judiciously because all
the code to actually write to the flight controller is consolidated in the
VehicleConfigurationHelper class.  So really this should only be used for
getting settings.
SetupWizard: use getObjectManager() in the outputCalibration page
NavigationWizard: add failsafe page

This page checks that the user can toggle failsafe mode by turning
the transmitter on and off