Add simplified Chinese translation

[xiaoxinpro]

Add simplified Chinese translation

[jc21]

This is an automated message from CI:

Docker Image for build 1 is available on DockerHub as jc21/nginx-proxy-manager:github-pr-2052

Note: ensure you backup your NPM instance before testing this PR image! Especially if this PR contains database changes.

[xiaoxinpro]

The translation doesn't work, the language is fixed to en in the front-end code, I hope this can be fixed.

Related source code

[jc21]

This version 2 doesn't have a language switcher in the UI, despite having the foundations for language support. Verison 3 does have this however, but it's still work-in-progress.

[xiaoxinpro]

Chinese translation has been completed, please visit https://github.com/xiaoxinpro/nginx-proxy-manager-zh this project.

中文翻译已完成，请访问这个项目 https://github.com/xiaoxinpro/nginx-proxy-manager-zh

[leic4u]

@xiaoxinpro 可以翻译下v3吗，v3上周刚发布了一个版本

[xiaoxinpro]

@leic4u V3版本目前还处于测试阶段，请等待官方发布Releases版本，根据情况会及时展开翻译工作。

[nginxproxymanagerci[bot]]

Docker Image for build 7 is available on DockerHub as jc21/nginx-proxy-manager:github-pr-2052

Note: ensure you backup your NPM instance before testing this PR image! Especially if this PR contains database changes.

[github-actions[bot]]

PR is now considered stale. If you want to keep it open, please comment :+1: