reduce length of recruiting/tracking section

When running this tutorial, the recruiting/tracking section took too long. The content needs to be cut down. Below are some thoughts on how to achieve this, but other contributors might have different ideas. Keep in mind that a preferred teaching strategy is to use exercises to teach content, not just practice what was already written elsewhere.

Possible approaches:

- Trim "Who to recruit" section down to a couple of sentences (maybe abandoning the RQ/value prop/target pop approach?)
- trim text overall to be more concise
- cut exercise 5
- move some content into collapsable divs, signaling it can be skipped if need be (maybe the stuff one anonymity in the "Tracking participation" section?)

**Before addressing this issue**, please leave a comment describing your approach so that others can assist without duplicating work. Tag a reviewer (e.g. @jlcohoon) as well.
**Please check that the "Overview" and "Key Points" don't need adjusting after your edits**

Carpentries info on formatting the different kinds of callouts and collapsable content like exercises might be useful: https://carpentries.github.io/sandpaper-docs/instructor/component-guide.html
https://carpentries.github.io/lesson-development-training/lesson-content.html#adding-exercises

Start by reviewing the recruiting/tracking section, including “Who to recruit” and “Tracking participation,” then compare the linked Carpentries guidance on callouts, collapsible content, and exercises. Propose an approach in an issue comment and tag a reviewer before editing. Done means the section is shorter, the exercise and optional content choices are resolved, and “Overview” and “Key Points” remain consistent.

Written by the indexing model from the issue text.