Uses geocoder gem to get city, country code and ISP name from given IP address.
Uses i18n_data gem to transform country code to country name, e.g. JP to Japan.
Location and ISP info is displayed in the sign in notification email when found,
see http://gdk.local:3000/rails/mailers/notify/unknown_sign_in_email.html

Changelog: added
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/163914