Add support for other commercial models

[kasnerz]

https://ai.google.dev/gemini-api/docs

https://docs.anthropic.com/en/api/getting-started

Edit: I would be great to use a single library for all the models. Potentially this one? https://github.com/BerriAI/litellm

[oplatek]

This is a useful library
https://github.com/andrewyng/aisuite

It supports OpenAI, vLLM OpenAI client (because it supports OpenAI API), and Ollama.

The only remaining question is if it supports extra arguments needed for structured decoding with OpenAI and vLLM