feat: add Chinese docs translation

[DDDDD12138]

Description

Add Chinese documentation, detailed comparison with the original English can be found in this commit.

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[cexbrayat]

Thanks for the PR @DDDDD12138 !

As I don't understand Chinese, I'll try to find someone on the team who can proof-read this.

[Jinjiang]

Thanks for the contribution!
Update: I'm calling @vuejs-translations zh-cn team to review this PR.

[Jinjiang]

Well, after reviewing some docs, I've found quite a lot of formatting issues. I would recommend you to refer to this Chinese translation guide for more details. And in practice, you can feel free to run zhlint, the tool we use for Vue Chinese docs, on your translation files. Usually for most of the issues, this tool can help you to figure them out and fix them. We can discuss further if you have any questions in any particular cases.

After solving the formatting issues, we can merge it ahead (probably with a "in review" marks on the pages somewhere) and then review the docs piece by piece as the second step.

Thanks.

[DDDDD12138]

ok, I'll deal with it later.

[veaba]

优化描述更改中文斜体用法

[veaba]

文件太大没法加 sug，斜体使用

另外补充：vue-router.md L289 部分。
```suggestion
然而，在这种情况下，我们没有可以等待的 *hasNavigated* 钩子。一种替代方法是使用从 Vue Test Utils 导出的 `flushPromises` 函数：

添加太大 500 了。

[DDDDD12138]

添加太大 500 了。

这个指的是啥？我这边好像没显示出来🤔

[veaba]

添加太大 500 了。

这个指的是啥？我这边好像没显示出来🤔

那个 vue-router.md 文件太大，没办法对指定位置添加 Suggetion，Github 报 500了。

改动部位：_hasNavigated_ 改为 *hasNavigated* 就可以了。

@Jinjiang 我这边 review 结束了，再交叉检查下应该可以了。

[Jinjiang]

I've added these in-review labels and created this epic issue #2561 for further review.

For this PR I will merge soon. Thanks all.