Rag CLI (#10193)

docs/index.rst

docs/module_guides/loading/ingestion_pipeline/root.md

docs/module_guides/querying/pipeline/root.md

...anding/putting_it_all_together/putting_it_all_together.md

docs/use_cases/rag_cli.md

llama_index/chat_engine/types.py

llama_index/command_line/command_line.py

llama_index/command_line/rag.py