NavigationMapRoute style dependency

NavigationMapRoute is dependent on the valid Map Style object, even though it requires only the MapboxMap as an argument. More so, the NavigationMapRoute manages style changes under the hood, which makes the usage of the class unintuitive - the object has be created in the OnStyleLoaded callback, but it cannot get recreated in one, because it'll throw:

E/Mbgl-MapChangeReceiver: Exception in onDidFinishLoadingStyle
    com.mapbox.mapboxsdk.style.sources.CannotAddSourceException: Source mapbox-navigation-arrow-shaft-source already exists
        at com.mapbox.mapboxsdk.maps.NativeMapView.nativeAddSource(Native Method)
        at com.mapbox.mapboxsdk.maps.NativeMapView.addSource(NativeMapView.java:839)
        at com.mapbox.mapboxsdk.maps.Style.addSource(Style.java:115)
        at com.mapbox.services.android.navigation.ui.v5.route.MapRouteArrow.initializeArrowShaft(MapRouteArrow.java:191)
        at com.mapbox.services.android.navigation.ui.v5.route.MapRouteArrow.initialize(MapRouteArrow.java:165)
        at com.mapbox.services.android.navigation.ui.v5.route.MapRouteArrow.<init>(MapRouteArrow.java:106)
        at com.mapbox.services.android.navigation.ui.v5.route.NavigationMapRoute.redraw(NavigationMapRoute.java:365)
        at com.mapbox.services.android.navigation.ui.v5.route.NavigationMapRoute.access$000(NavigationMapRoute.java:38)
        at com.mapbox.services.android.navigation.ui.v5.route.NavigationMapRoute$1.onDidFinishLoadingStyle(NavigationMapRoute.java:331)
        at com.mapbox.mapboxsdk.maps.MapChangeReceiver.onDidFinishLoadingStyle(MapChangeReceiver.java:198)
        at com.mapbox.mapboxsdk.maps.NativeMapView.onDidFinishLoadingStyle(NativeMapView.java:1035)
        at android.os.MessageQueue.nativePollOnce(Native Method)
        at android.os.MessageQueue.next(MessageQueue.java:326)
        at android.os.Looper.loop(Looper.java:160)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

The class should be refactored to be operational without the Style object and leverage the redraw logic for each style load.

The solution here might also resolve https://github.com/mapbox/mapbox-navigation-android/issues/2027.

Start with NavigationMapRoute.redraw and its onDidFinishLoadingStyle callback, then inspect MapRouteArrow initialization where the duplicate source exception occurs. Refactor the class so it operates with MapboxMap alone and uses redraw on each style load; done means recreating or reloading the route does not add an existing source.