agents: internationalize and add Chinese prompt

[Alan796]

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If non-English questions are inputed, the agents won't work well with the English prompt, so I'm internationalizing agents and adding Chinese prompt. Other languages can be supported too.

[tmc]

Looks great, thanks for adding this, have a few nits.

[Alan796]

@tmc OK, thank you for the opinions, the nits are resolved, please review again.

[Alan796]

Wait, there are conflicts, I will resolve them now.

[Alan796]

OK, conflicts are resolved.

[codexc]

"牛逼"非常精髓了！

[iHuangYaoshi]

"牛逼"这个词会不会让一些英文语料训练的大模型懵逼