Refactor code_review into a Pandoc+Reveal.js presentation

As of ~October 2021, I no longer have a Mac laptop at my disposal outside of my work laptop, so I should use Keynote on my old laptop to reimplement the presentation in Markdown. Some of the animations might not translate well and the slide content and layout definitely don't work well with the default Reveal.js theme, so this is not a small amount of work.

Locate the existing code_review presentation and review its current Keynote-based source before planning the Markdown conversion. Check how Pandoc and Reveal.js are expected to represent the existing slide content, layout, and animations. Done means the presentation is reimplemented in Markdown with acceptable Reveal.js output and the known animation limitations are addressed.

Written by the indexing model from the issue text.