Implement additional LLMs

[grumpyp]

I found https://litellm.ai/

it seems like an easy integration for even more open-source LLMs.

What do you think?

[ishaan-jaff]

made a PR: #129

[Aditi840]

@grumpyp , I would like to work on this issue, just give me an overview on what needs to be done.

[grumpyp]

@Aditi840 hi there, would you please take another open issue?

[Aditi840]

@grumpyp , ok will do that.