feat: add trusted client IP support for multiple gateways

snippets/proxy.conf.template

@@ -1,13 +1,17 @@
+# restrict access
 if ($allow_access = 0) {
     return 403;
 }
 
 # set headers
 proxy_set_header Host              $host;
-proxy_set_header X-Real-IP         $remote_addr;
-proxy_set_header X-Forwarded-For   $proxy_add_x_forwarded_for;
+proxy_set_header X-Real-IP         $trusted_client_ip;
+proxy_set_header X-Forwarded-For   $trusted_client_ip;
 proxy_set_header X-Forwarded-Proto $scheme;
+
+# clean headers
 proxy_set_header X-Origin-Token    '';
+proxy_set_header EO-Connecting-IP  '';
 
 # enable websockets: http://nginx.org/en/docs/http/websocket.html
 proxy_http_version 1.1;