GeoIP support for timezones and admins

[shazow]

It would be nice if we could automagically detect users' timezones based on their IP.

Another fun feature would be to add the detected country for admin /whois output.

The challenge here is that it's hard to do GeoIP without querying an external service and that's less fun. At the very least, features that ping external services should be disableable. It should certainly fail gracefully (ie. not crash) if using an external service and it's not available.

If we can figure out a non-resource-intensive-yet-reliable way to do this without an external service, then I'm a strong +1.

One option is to use something like https://github.com/oschwald/geoip2-golang and let the user supply the database. Though would be nice if we could automagically fetch it.

Another option would be to have an "official" ssh-chat provider of this database, or at least a redirect to a download URL.

Seems distros have no problem with downloading it from the source: https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/services/misc/geoip-updater.nix

No shortage of random Go packages downloading it:
https://github.com/search?q=geolite.maxmind.com%2Fdownload%2Fgeoip%2Fdatabase+language%3Ago&type=Code