Add example for python notebook with partial & columnar updates

[Wumpf]

So far we crammed everything into cube.ipynb so was a bit unsure from where to link it. Not linked anywhere right now but I figure better than not having it.

[github-actions]

Latest documentation preview deployed successfully.

Result	Commit	Link
✅	d1591f0	https://landing-l71bdlbu5-rerun.vercel.app/docs

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