Implement jupyter-ai like interface

[MarcSkovMadsen]

I've now access to Jupyter-ai in my JupyterHub. Its provides an interface to a RAG.

They have implemented a pretty amazing UI where its really, really easy to learn. A user just needs to write /learn path/to/documents in the input widget. And it will be learned in a split second via a very efficient implementation using Dask. See https://github.com/jupyterlab/jupyter-ai/blob/ec75ba827945c48b6e707c6cc4835eb5c561b616/packages/jupyter-ai/jupyter_ai/chat_handlers/learn.py#L138.

You should try it out and learn from their implementation @ahuang11 if you ever want to implement a chat interface for Panel or HoloViz. You can add markdown, python code, notebooks etc. in a split second and start using.

I would love for us to have a similar reference implementation. Would be so useful.