etcd component init IsHealth check Get operation context set timeout

Link to an issue

hanlde issue11

etcd config 添加了 timeout 配置， IsHealth 方法在 Get health key 的 context 添加对应的超时设置

etcd config 添加属性以及方法，如果配置无效，则方法会返回默认值 3s，在IsHealth客户端调用前获取config，并调用其方法获取 timeout 配置，并最后根据 timeout 创建 context，传入 Get

config.yaml 添加对应的 timeout 配置，并停止 etcd 服务，程序将出现超时

[x ] Link to an issue if it really related.
[ x] At least describe what this PR does.
[ x] Use rebase to confirm that current branch doesn't conflict with main branch.
[ ] Unit tests. At least do not reduce the unit test coverage.
[ ] Checked and updated guidelines.md which used to describe how to build, deploy and use DouTok.