Add computed X-Request-ID to the access logs

* https://docs.nginx.com/nginx/admin-guide/monitoring/logging/
* http://nginx.org/en/docs/http/ngx_http_log_module.html#log_format
* https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/log-format/

Author: itskingori

config/log.conf

@@ -1,6 +1,6 @@
 log_format main '$remote_addr - $remote_user [$time_local]  $status '
                 '"$request" $body_bytes_sent "$http_referer" '
-                '"$http_user_agent" "$http_x_forwarded_for"';
+                '"$http_user_agent" "$http_x_forwarded_for" $proxy_x_request_id';
 
 access_log /dev/stdout main;
 error_log /dev/stdout warn;