proxy configuration choice between apache and nginx
Within SADE, apache is mostly used as proxy. I think the reason for this is that most of the projects use Shibboleth to secure access to parts of the application. And there is no Shibboleth module for NGINX. I think in theory it is possible (https://github.com/nginx-shib/nginx-http-shibboleth), but AFAIK we don't have this module.
So the enable proxy configuration stuff should be extended to switch between apache and nginx.