[feature] Alternative map provider <UrlTile>

[tamis-laan]

Using this library is great for adding web support for react native maps. However it forces you to use google maps. It would be awesome if we would be able to support <UrlTile> so we can use an alternative tile provider like open street maps. Or host your own tile server with OptenMapTiles:

https://openmaptiles.org/
https://hub.docker.com/r/klokantech/tileserver-gl