Add MapBox as a provider for reverse Geocoding

[rbino]

Right now we only support IPBase, which has some limitations. We should explore adding support for MapBox.

[davidebriani]

IPBase converts an IP address to a location, so we should review tools with similar functionality.

MapBox has a generous free tier but it does not support IP -> Location conversion as of now.

Other solutions that could be considered:

• https://www.ip2location.io/ currently has 30K free API calls each month.
• https://github.com/sapics/ip-location-db or similar offline databases.