Adding Databricks RAG example recipe

[anushadudi]

What does this PR do?

Adding Databricks RAG example with hts code classification usecase.
The task for the model is to output a 10 digit hts code given a product description.
The following approach leverages RAG with Databricks vector search and structured JSON outputs to tackle the issues of response inconsistencies and format adherence.

Feature/Issue validation/testing

Please describe the tests that you ran to verify your changes and relevant result summary. Provide instructions so it can be reproduced.
Please also list any relevant details for your test configuration.

• Tested the notebook on Databricks
  Notebook has logs

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• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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