Option to set API endpoint

[xmoiduts]

[This suggestion may be very immature, but I still put it here.]

Currently, more GenAI providers are emerging, followed by aggregate API providers. They may use OpenAI-compatible API schemes to simplify the integration process to other competitor Chat AI models.

Though simplified, an API endpoint other than OpenAI is still needed. By providing the ability to set API endpoint, this GPT shell may have the possibility to directly access other Gen AI platforms.

Example: https://api../v1/chat/completions