[zh_CN] Translation of FireFly documentation for Chinese, Simplified

[Chengxuan]

What would you like to be added?

• Translations of doc-site to Chinese, Simplified.
• as this is the first translation, a language switcher in the documentation site will need to be added, and the folder layout will need to be proposed

Why is this needed?

as well put by @Shawn-Shaw-x in https://discord.com/channels/905194001349627914/1154921177207275520/1325036925660172288:

Many developers in China mainland who are not familiar with english. They also want to learn this project or to make their own contributions on this project.

[EnriqueL8]

We would need to take into consideration the documentation that is generated from code. Things such as error message, reference types, Swagger APIs, etc...

[Shawn-Shaw-x]

We would need to take into consideration the documentation that is generated from code. Things such as error message, reference types, Swagger APIs, etc...

It's that means we need to translate in comment?

[Chengxuan]

@Shawn-Shaw-x The intention is to avoid the translation of auto-generated content. Please try to avoid translation of the content that is likely to be generated from the code (use your own judgment plus the list above)

[Shawn-Shaw-x]

judgment

Got it!