Feature: QR shortcodes

[cscheid]

TODO

• Figure out why data URIs don't work well on PDF format
• support usage in metadata

Minimal example

---
title: qr code test
format: revealjs
---

## Neat!

See source for this PR:

{{< qr https://github.com/quarto-dev/quarto-cli/pull/9021 width=200px height=200px >}}

[cscheid]

Figure out why data URIs don't work well on PDF format

This is a separate bug that's easy to fix in its own PR.

support usage in metadata

I think I want to fix this in its own PR as well. Right now, no TypeScript shortcode works in metadata.

Ideally we would be resolving this shortcode in Lua instead of TypeScript. The problem is that there's no easy-to-use QR code library in Lua, and there's one in TypeScript.

[cscheid]

I'm going to close this because before we fix our deno bundling, this feature won't work;

• We can't use the skypack version of qrcode in deno because it's confused about browser vs server setting and expects the canvas API to exist
• We can't use the npm version of qrcode in Quarto because deno doesn't support deno bundle with NPM imports.