feat: 机器新增备注字段,其他优化

server/mayfly-go.sql

@@ -88,6 +88,7 @@ CREATE TABLE `t_machine` (
   `username` varchar(12) COLLATE utf8mb4_bin NOT NULL,
   `password` varchar(32) COLLATE utf8mb4_bin DEFAULT NULL,
   `status` tinyint(2) NOT NULL COMMENT '状态: 1:启用; -1:禁用',
+  `remark` varchar(255) COLLATE utf8mb4_bin DEFAULT NULL,
   `need_monitor` tinyint(2) DEFAULT NULL,
   `create_time` datetime NOT NULL,
   `creator` varchar(16) COLLATE utf8mb4_bin DEFAULT NULL,