refactor: rename i18n/*/docusaurus-plugin-content-docs to i18n/*/docs (#588)

Drops the leftover docusaurus name from the translated content directories.

- git mv i18n/{en-us,zh-cn,zh-tw}/docusaurus-plugin-content-docs -> i18n/{locale}/docs (pure renames, content unchanged)
- update the paths in packages/content-loader/src/products.ts, scripts/cut-version.mjs and sites/docs/README.md

current.json / version-*.json keep their names and stay beside the content.

Verified: pnpm build succeeds, 6690 pages built.

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Reviewed-on: https://gitea.com/gitea/docs/pulls/588
Reviewed-by: Zettat123 <[email protected]>

i18n/zh-cn/docs/version-28/administration/git-lfs-support.md

@@ -0,0 +1,24 @@
+---
+date: "2023-05-23T09:00:00+08:00"
+slug: "git-lfs-setup"
+sidebar_position: 12
+
+aliases:
+  - /zh-cn/git-lfs-setup
+---
+
+# Git LFS 设置
+
+要使用 Gitea 内置的 LFS 支持，您需要更新 `app.ini` 文件：
+
+```ini
+[server]
+; 启用 git-lfs 支持。true 或 false，默认为 false。
+LFS_START_SERVER = true
+
+[lfs]
+; 存放 LFS 文件的路径，默认为 data/lfs。
+PATH = /home/gitea/data/lfs
+```
+
+**注意**：LFS 服务器支持需要服务器上安装 Git v2.1.2 以上版本。