Retrieval Augmented Generation with LLM Demo

[danielfleischer]

• Added a new RAG + prompt + LLM UI (demo).
• Added a RAG + prompt + LLM example config and notebook.
• Updated main README with updates sub-section.
• Updated the main README.
• Updated run_demo.py to include all the options to run a demo
  • UI
  • UI + service
  • UI +
• Added RAG + synthesized augmented prompt + LLM notebook example.