Hope to increase custom host function

[jaychoubaby]

Sometimes we access OpenAI not necessarily through https://api.openai.com/. Due to network reasons, sometimes we will build a proxy domain for requests. We hope to support custom host functionality, not just for OpenAI, but also for other AI language models. In most cases, we use this method for proxy access. Thank you very much for your efforts and hope you can consider this feature, which is really important for users in China and some other countries.

[jaychoubaby]

When there is a network blockade, we cannot make requests through https://api.openai.com/v1/chat/completions. However, we have set up a domain proxy ourselves, and it is possible to access it normally through https://${my-domain}/v1/chat/completions. I noticed that the current code has hardcoded "https://api.openai.com/" as a fixed value, which prevents us from using spring-cloud-alibaba-ai properly.