Let's add some helpers to make accessing simple configuration values simpler. The helpers are used in the followup patches. GlobalConfiguration::option ensures that no value is returned rather than a value of YamlObject::empty. Signed-off-by: Milan Zamazal <mzamazal@redhat.com> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>