Add managerFrontWorker thread pool, responsible for managing front-side connections (9066) see: [doc](https://actiontech.github.io/dble-docs-cn/history/develop/1.config_file/1.02_bootstrap.cnf.html#:~:text=%E6%AD%A3%E6%95%B4%E6%95%B0-,managerFrontWorker,-%E5%89%8D%E4%BE%A7%E7%AE%A1%E7%90%86)