docs: rag chatbot tutorial (#8929)

* minimal-working-code

* remove-old-files-and-add-new-content

* cleanup

* swap-in-faiss

* more-content

* initial-content

* remove-files

* remove-unused-image-file

* Apply suggestions from code review

Co-authored-by: April I. Murphy <36110273+aimurphy@users.noreply.github.com>

* differentiate-vector-db

* Apply suggestions from code review

Co-authored-by: Melissa Herrera <85907755+melienherrera@users.noreply.github.com>

* use-langflow-js-client

* next-steps

* Apply suggestions from code review

Co-authored-by: April I. Murphy <36110273+aimurphy@users.noreply.github.com>

* docs-review

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Co-authored-by: April I. Murphy <36110273+aimurphy@users.noreply.github.com>
Co-authored-by: Melissa Herrera <85907755+melienherrera@users.noreply.github.com>