Recordings component

[jsoules]

This PR Implements a generic framework for handling static and dynamic content cards, which should make it easier to maintain Spike-Front content in the future. Static content for an entire page of multiple sections can now be written and managed in a single (validation-compliant) Markdown file, with an overall page title and section titles as well as effective control of the sidebar labels. This model includes a custom hook (in the general programming sense, not the React sense) to modify or apply special handling to any of the sections defined in Markdown via a component-specific function. We can also add non-Markdown-based additional/dynamic content after the static content defined in the Markdown file (as in the Recordings page, which renders a list of study sets based on dynamic retrieved data).

Most of the parsing system is in src/components/shared/MarkdownHandling.tsx (though I could see a good argument for splitting it up more). I've written hopefully enough comments that we'll know how it works next time.

Based on these changes, I probably ought to revisit the Algorithms and maybe Metrics sections, but it's not a high priority.

Current merge plan should be this PR into about-page branch, then that into the Algorithms branch, and then that into main.

This version is up on vercel: https://othismos-jsoules.vercel.app