Merge pull request !57 from freesky-edward/license

Merge pull request !56 from ZhengyuhangHans/doc_en

Merge pull request !53 from ZhengyuhangHans/master

Merge pull request !54 from ZhengyuhangHans/Branch_master-18N1

Merge pull request !44 from freesky-edward/oauth

Merge pull request !52 from ZhengyuhangHans/master

Merge pull request !51 from ZhengyuhangHans/master

!50 1. Delete the prompt page that "文档中心正在构建中" 2. Add four document links:“安装指南”、“管理员指南”,"容器用户指南","虚拟化用户指南" to Docs module.3. Change the height of the gitee icon on the large screen to 18px 4.Change the button "下载ISO" to  "下载openEuler-1.0-aarch64-dvd.iso".
Merge pull request !50 from ZhengyuhangHans/master

1. Delete the prompt page that "文档中心正在构建中" 2. Add four document links:“安装指南”、“管理员指南”,"容器用户指南","虚拟化用户指南" to Docs module.3. Change the height of the gitee icon on the large screen to 18px 4.Change the button "下载ISO" to  "下载openEuler-1.0-aarch64-dvd.iso".

Merge pull request !48 from haomintsai/master

Signed-off-by: Ncaihaomin <c00416947@china.huawei.com>

!47 1.add checksum file download link in Download page. 2.change the gitee icon size to 18px. 3.Change the font color of the secondary menu to black.
Merge pull request !47 from ZhengyuhangHans/master

2.change the gitee icon size to 18px.
3.Change the font color of the secondary menu to black.

Merge pull request !45 from cynthia_xh/l-cyn

Merge pull request !43 from Fred_Li/hdc_typo

Merge pull request !42 from Fred_Li/master

Fix some link errors in the webpage https://openeuler.org/en/developer.html (both English and Chinese).