wip: created osm and googlemap providers classes, added env support

[tarunsinghofficial]

Tasks Completed:

• Added the osm support at .env level
• Created the GoogleMapProvider & OpenStreetMapProvider classes as providers.
• Implemented the plugin architecture for other maps in future.

Issues In-progress:

• change icons in OSM
• display the route in OSM & google maps
• display stops properly in google maps

[aaronbrethorst]

@tarunsinghofficial this is looking good! I noticed a few issues and areas for improvement, though:

• Move new StopMarker() into GoogleMapProvider
• Fix an error thrown by the Google Maps library when zooming in (see TODO in GoogleMapProvider)

I think the approach you're taking of creating the map provider inside of the MapView (which I renamed, by the way), is fine for the moment but I would recommend considering a dependency injection approach instead. i.e. the parent component to MapView figures out the correct map provider and gives that to MapView.