Make download and preparation of the geoname dataset and countrycodes table part of the package installation.

[BoZenKhaa]

Right now, the data is fetched when Geocoder is run for the first time. It would make more sense to move this step to the installation step to avoid runtime errors related to missing/incomplete data.

• Add build step to the package
• Store the datasets in scratch spaces

[vchuravy]

I think downloading the data to Scratch would be a good improvement.
Alternatively using the artifact system, but generally being lazy with the download is fine.