Incorporate panel sets

[coatless]

Thanks to cscheid's response: quarto-dev/quarto-cli#9646 (reply in thread)

There's now a way forward to accomplishing:

1. showcasing what options are being used so we're not copying and pasting on the custom cell
2. offering rendered results alongside the interactive cell (c.f. Registering a custom code cell engine when using a lua filter and knitr backened quarto-dev/quarto-cli#4761 (reply in thread))

With this work out of the way, we can move to incorporating it inside of altdoc.

[coatless]

quarto-panelize is now available:

https://github.com/coatless-quarto/panelize

We probably should add a documentation entry describing its use.

Ditto with adding a new entry showing an application with altdoc to create package websites with interactive examples.

https://github.com/coatless-r-n-d/quarto-webr-in-altdoc