Deliver static files by Drupal

There will be a variable NGINX_DRUPAL_FILE_PROXY_URL for the nginx container so that we can deliver files from Drupal or the live site instead of Nginx. Details see https://github.com/wodby/drupal-nginx/issues/29

This is now possible with this environment variable:

nginx:
    image: wodby/drupal-nginx:7-1.13
    environment:
        NGINX_DRUPAL_FILE_PROXY_URL: http://live_server.com

mentioned in commit e30dd8ea

closed