Add YiAi model client

[wb04307201]

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this PR is add YiAi model client and has passed unit testing.

I can provide my api_key if needed for testing

the PR content:

chat client spring starter unit test chat client documents For some reasons, products from OpenAI and others can't be directly used in Chinese Mainland.

YiAi is a big model platform, A variety of models are offered, among which Yi-1.5 are fully free. Although their API design is quite strange.

the link: YiAI