增加Workhorse和GitLab Shell的开发入门

查看渲染后的版本：

• Workhorse开发入门：https://jihulab.com/gitlab-cn/developer-guide/-/blob/nanmu/add-go-docs/docs/golang/workhorse/kickstart/index.md
• GitLab Shell开发入门：https://jihulab.com/gitlab-cn/developer-guide/-/blob/nanmu/add-go-docs/docs/golang/gitlab-shell/kickstart/index.md

Closes https://jihulab.com/jihulab/hr/okr/engineering/okr-nanmu42/-/issues/17, https://jihulab.com/jihulab/hr/okr/engineering/okr-nanmu42/-/issues/18

/cc @prajnamas