Add Config Option to Overwrite OpenAI's API Base

[GOODBOY008]

Description:

It would be beneficial to add a configuration option that allows users to overwrite the OpenAI API base.

Use Case:

Users facing issues with OpenAI's regional restrictions, where the default API base may not be accessible due to geo-blocking or other limitations.

[mrubens]

That makes sense. I think a lot of users will use the OpenAI-compatible provider for that, but it seems like we could add a custom base URL option to the native OpenAI provider like we do for Anthropic and others.

[GOODBOY008]

@mrubens Thank you for your quick reply. I am willing to contribute this feature.

[mrubens]

Great!