RAG Ingestion is used deprecated Llama Stack APIs

[franciscojavierarceo]

Llama Stack has moved to Open Responses which means the Llama Stack RAG demos should instead focus on using the OpenAI Compatible APIs like Files, Vector Stores, Search, and Respones for our demos.

It would be great if the demos could be cleaned up.

[sauagarwa]

We are working on it, and have upgraded the code base to use responses API of llamastack based on llamastack-0.6.0