Refactor docs (#21627)

This patch:
- Rename some files( `.md` to `.en-us.md`), fix missed translation copy
- Update link which shoud be refer to `../hacking-on-gitea/` instead of
`../make/` (outdated)
- Update `_redirects`:
  -  redirect `/{zh-cn|fr-fr}/make/` to `../hacking-on-gitea/`
  - redirect `/zh-cn/third-party-tools/` to `/zh-cn/integrations/`
- Delete duplicated/outdated files.
- Update menu `weight` of developers.zh-cn.md

Signed-off-by: Xinyu Zhou <i@sourcehut.net>

docs/content/doc/usage/git-lfs-support.en-us.md

@@ -0,0 +1,30 @@
+---
+date: "2019-10-06T08:00:00+05:00"
+title: "Usage: Git LFS setup"
+slug: "git-lfs-setup"
+weight: 12
+toc: false
+draft: false
+menu:
+  sidebar:
+    parent: "usage"
+    name: "Git LFS setup"
+    weight: 12
+    identifier: "git-lfs-setup"
+---
+
+# Git Large File Storage setup
+
+To use Gitea's built-in LFS support, you must update the `app.ini` file:
+
+```ini
+[server]
+; Enables git-lfs support. true or false, default is false.
+LFS_START_SERVER = true
+
+[lfs]
+; Where your lfs files reside, default is data/lfs.
+PATH = /home/gitea/data/lfs
+```
+
+**Note**: LFS server support needs at least Git v2.1.2 installed on the server