nixos/nginx: Do not remove headers while proxying

Removing the `Accept-Encoding` header breaks applications which may
produce already compressed content.

Removing this header is staded in the nginx docs but is ment as an
example, not as an recomendation.

nixos/modules/services/web-servers/nginx/default.nix

@@ -34,7 +34,6 @@ let
     proxy_set_header        X-Forwarded-Proto $scheme;
     proxy_set_header        X-Forwarded-Host $host;
     proxy_set_header        X-Forwarded-Server $host;
-    proxy_set_header        Accept-Encoding "";
   '';
 
   upstreamConfig = toString (flip mapAttrsToList cfg.upstreams (name: upstream: ''