Fetch model list dynamically

https://twitter.com/fireworksai_hq/status/1781548519398252918

> We do support OpenAI-compatible endpoint for it:
>
> `curl -H "Authorization: Bearer <API_KEY>" api.fireworks.ai/inference/v1/m…`
> 
> or `Models.list()` with our or OpenAI SDK, e.g. pypi.org/project/firewo…
