Nested columns tutorial

[writer-jill]

Jupyter notebook tutorial on working with nested columns

This PR has:

• been self-reviewed.

[317brian]

This is great! Really shows what you can do with nested columns. A few minor suggestions/changes

[317brian]

2 more minor things

[317brian]

🥳 but your beginning disappeared with the apache license and intro stuff, so add that back and we're good.

[github-actions]

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[techdocsmith]

@writer-jill we can use the Kafka notebook as a template to get this one fixed & into the docs

[writer-jill]

Stale PR - closing & will open a new one for this tutorial.