Fix MapBox support in ondemandnavi application

While doing some ad hoc testing, I tried enabling using MapBox tiles in the ondemandnavi application, and noticed the format of the style URLs for QtLocation seems to have changed at some point, as the application gets errors trying to download tiles now.  The fix is a relatively straightforward tweak to the default style URLs in ondemandnavi and the naviconfig.ini file installed by the ondemandnavi-config recipe.