Remove LangChain dependency for LLMs

[deepakachu-aiplanet]

• Remove LangChain dependency for LLMs in OpenAGI and write functions using the official API for all major LLM providers

[AdvH039]

Can I work on this please? Thanks.

[hannahbellesheart]

If I may , IMHO, I would leave this as an option, ..Implement the official API, ABSOLUTELY, but implement them in such a way that LangChain remains, if for nothing more than to be a teachable component in the grand scheme of things. Some Microsoft tutorials still call for the use of LangChain...Some examples show how to convert LangChain. Keeping LangChain in place while still implementing the Offical APISmakes for a much more flexible experience....

[tarun-aiplanet]

Can I work on this please? Thanks.

Sure. Assigned it to you, please mark this issue and open the PR