services: move 'media' to 'modules' instead

Its not actually a service, but more of a configuration needed by some
services. Therefore it belongs in modules.

services/default.nix

@@ -10,7 +10,6 @@
     ./indexers.nix
     ./jellyfin.nix
     ./matrix.nix
-    ./media.nix
     ./miniflux.nix
     ./nextcloud.nix
     ./nginx.nix

services/media.nix

@@ -1,16 +0,0 @@
-# Abstracting away the need for a common 'media' group
-
-{ config, lib, ... }:
-let
-  mediaServices = with config.my.services; [
-    calibre-web
-    jellyfin
-    pirate
-    sabnzbd
-    transmission
-  ];
-  needed = builtins.any (service: service.enable) mediaServices;
-in
-{
-  config.users.groups.media = lib.mkIf needed { };
-}