In order to circumvent the usage quota of Google Maps
the map provider was changed to be MapBox now. Additionally
the maps implementation was refactored to be better extendable
in future.
If currently following another user, and the map gets moved,
enable a recenter button to update the location to the currently
selected location of the user.
Added some base GoogleMap widget logic and a way to listen to ones own
location updates. In future this needs to be extended with a way to
listen to the updates of other users.
