Add Initial README (#205)

## 🥞 Stacked PR
Use this [link](https://github.com/databricks/sdk-js/pull/205/files) to
review incremental changes.
- [**stack/readme**](#205)
[[Files changed](https://github.com/databricks/sdk-js/pull/205/files)]

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## Summary

This PR adds an initial Readme for the Repo. Right now, it adds very
minimal details. But this set as a starting point for the README.

## How is this tested?

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N/A

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Co-authored-by: Renaud Hartert <renaud.hartert@databricks.com>

Author: parthban-db