nixos/tandoor-recipes: revert 'GUNICORN_MEDIA=1'

Quoting from upstream's documentation [1]:

> Basically everyone recommends not doing this. Please use [a webserver]
> to handle media file serving.

Given that this commit broke the module for unrelated reasons, I've
decided to just revert it and let downstream users make the choice of
easy vs. secure.

[1]: https://docs.tandoor.dev/system/configuration/#gunicorn-media

This reverts commit e8c56de827.

nixos/modules/services/misc/tandoor-recipes.nix

@@ -11,7 +11,6 @@ let
     DEBUG = "0";
     DEBUG_TOOLBAR = "0";
     MEDIA_ROOT = "/var/lib/tandoor-recipes";
-    GUNICORN_MEDIA = true;
   } // optionalAttrs (config.time.timeZone != null) {
     TZ = config.time.timeZone;
   } // (