Add example, which showcases `NavigationMapView` injection into `NavigationViewController`.

[MaximAlien]

In scope of this ticket new example should be created, which shows how NavigationMapView injection into NavigationViewController can be performed.

[MaximAlien]

Depends on mapbox/mapbox-navigation-ios#3576.

[1ec5]

For context, this example would demonstrate usage of the NavigationOptions.navigationMapView property added in mapbox/mapbox-navigation-ios#3186. An application that implements its own route preview view controller (because of mapbox/mapbox-navigation-ios#808) can more seamlessly transition from it to NavigationViewController by specifying NavigationOptions.navigationMapView. NavigationViewController will embed the specified NavigationMapView and manipulate it as if it were the built-in map view.

There remain some rough edges. NavigationViewController doesn’t clean up its modifications to the map view once the trip ends: mapbox/mapbox-navigation-ios#3576. Also, it would be nice to offer some animation by default: mapbox/mapbox-navigation-ios#3288. But it should be straightforward for applications to work around these issues in the meantime.