Restructure documentation. Now the documentation has installation, administration, usage, development, contributing the 5 main parts (#23629)

- **Installation**: includes how to install Gitea and related other
tools, also includes upgrade Gitea
- **Administration**: includes how to configure Gitea, customize Gitea
and manage Gitea instance out of Gitea admin UI
- **Usage**: includes how to use Gitea's functionalities. A sub
documentation is about packages, in future we could also include CI/CD
and others.
- **Development**: includes how to integrate with Gitea's API, how to
develop new features within Gitea
- **Contributing**: includes how to contribute code to Gitea
repositories.

After this is merged, I think we can have a sub-documentation of `Usage`
part named `Actions` to describe how to use Gitea actions

---------

Co-authored-by: John Olheiser <john.olheiser@gmail.com>

docs/content/doc/installation/from-binary.zh-cn.md

@@ -59,7 +59,7 @@ gpg --verify gitea-{{< version >}}-linux-amd64.asc gitea-{{< version >}}-linux-a
 
 ## 服务器设置
 
-**提示：** `GITEA_WORK_DIR` 表示 Gitea 工作的路径。以下路径可以通过 [环境变量]({{< relref "doc/advanced/environment-variables.zh-cn.md" >}}) 初始化。
+**提示：** `GITEA_WORK_DIR` 表示 Gitea 工作的路径。以下路径可以通过 [环境变量]({{< relref "doc/administration/environment-variables.zh-cn.md" >}}) 初始化。
 
 ### 准备环境
 
@@ -141,7 +141,7 @@ GITEA_WORK_DIR=/var/lib/gitea/ /usr/local/bin/gitea web -c /etc/gitea/app.ini
 
 您可以通过停止程序，替换 `/usr/local/bin/gitea` 并重启来更新到新版本。直接替换可执行程序时不要更改或使用新的文件名称，以避免数据出错。
 
-建议您在更新之前进行[备份]({{< relref "doc/usage/backup-and-restore.zh-cn.md" >}})。
+建议您在更新之前进行[备份]({{< relref "doc/administration/backup-and-restore.zh-cn.md" >}})。
 
 ### 1. 使用 systemd 重新启动 Gitea（推荐）