message: nginx.conf cleanup:
  default logging on warning (hides rewrite notice messages)
  add 'X-LAGOON' header to show hostname (easier debugging)
diff: -error_log /dev/stdout ${NGINX_ERROR_LOG_LEVEL:-notice};
  +error_log /dev/stdout ${NGINX_ERROR_LOG_LEVEL:-warn};
  events {
  worker_connections 1024;
  @@ -23,6 +23,8 @@ http {
  server_tokens off;
  + add_header X-LAGOON $hostname always;
  +
  uninitialized_variable_warn off;
  gzip on;
  