This reduces the confusion with the nixos/modules/deployment.nix module,
and should make it clearer that it can contain any configuration that
applies to all hosts on the grid.

This lets other modules override these settings.

As per @jcalderone and @florian videoconf on 2021-08-06.

- Remove custom handling of Let's Encrypt certs, use NixOs' ACME
  integration instead.

- Use NGINX for TLS termination.

NGINX does longest-prefix-match for selecting locations.

This should let it work for both enabled and disabled configurations

Using AWS is what causes it so using AWS can be what fixes it, too.

... This breaks the tie, thx to https://github.com/DBCDK/morph/issues/146