Add support for all Hugging Face Chat, Text models + OpenAI, Claude2, Cohere, Palm, Replicate models

[ishaan-jaff]

@hamelsmu noticed you were using meta-llama/llama-2-7b-hf. I'm making this PR to add support for all text2text and text generation models on Hugging Face.
I noticed most HF text models had different Input chat formats and outputs were not consistent.

liteLLM allows you to call all HF models (and the above mentioned providers) with a standard Input/Output interface - in the chatGPT format
More info here: https://github.com/BerriAI/litellm/

[ishaan-jaff]

@hamelsmu can you take a look at this PR when possible😊

Here's more info on how liteLLM works with HF models: https://docs.litellm.ai/docs/tutorials/huggingface_tutorial

[krrishdholakia]

Hi @hamelsmu we just added native support for Llama2's prompt formats, let me know if that helps