Migrate the reader to Quarto

[nick-ulle]

I'm working on migrating this reader to Quarto. This has several benefits:

• Faster rendering
• Additional formatting options (e.g., callout boxes)
• Clearer documentation

[nick-ulle]

Tracking comment for other tasks to make issues for and fix post-Quarto:

• [ ] Find a new data set for the ggplot2 examples in Chapter 3, because the current plots are quite ugly and difficult to read (they don't follow best practices)
• [ ] Review text for asides and notes that can be put in callout boxes to make it clearer to readers what the main ideas are
• [x] Use boldface instead of italics for vocabulary (suggested style for all DataLab readers)
• [x] Use callout boxes for learning objectives and make format consistent with JupyterBook readers
• [x] Fix FIXMEs in the appendix
• [x] Link to Intermediate R

[nick-ulle]

The Quarto version of the reader is now live.