Homelab updates

- Change domain to opdavies.uk as this works with HTTPS/SSL.
- Switch Nginx to Caddy.

nix/modules/nixos/features/homelab/pi-hole.nix

@@ -95,9 +95,5 @@ in
         wantedBy = [ "multi-user.target" ];
       };
     };
-
-    services.nginx.virtualHosts."pihole.localhost" = {
-      locations."/".proxyPass = "http://localhost:${toString port}/";
-    };
   };
 }