add steam module

sadly this has to be a system package until we find a non shitty way of
installing in through hm

nixos/trash/steam/default.nix

@@ -5,9 +5,9 @@
   ...
 }:
 with lib; let
-  cfg = config.options.trivium;
+  cfg = config.options.trivium.trash.steam;
 in {
-  options.trivium = {
+  options.trivium.trash.steam = {
     enable = mkEnableOption "steam settings";
 
     compatibilityPackages = mkOption {