Add support for other LLM providers

[amirhmoradi]

I would like to be able to use any model from OpenAI, Anthropic, Cohere, Forefront, HuggingFace, Aleph Alpha, Replicate, Banana and llama.cpp and more.

Some projects that provide this feature:

• https://github.com/nat/openplayground
• https://github.com/okisdev/ChatChat

I would love to contribute if your provide me with some help on how to get started :)