Add feature to exclude certain servers to users based on user's country code

[lunarthegrey]

Currently, it's possible that a user in a specific country can be provided with an access key from a server that is known to be blocked in their country (usually based on IP).

At the moment, there is no logic regarding this in the FCP.

We could implement a way to retrieve the user's country code in the request sent to the Cloudflare edge, then use that country code to make decisions about what server will be used to issue an access key.