Create a "prototype page"

[rkdarst]

Carpentries lessons are very standardized, with a fixed format. CR doesn't exactly have that, but we do have conventions. Perhaps we should think about what the typical conventions are, and how it differs from Cs.

Here is a prototype page I've made so far:
https://coderefinery.github.io/sphinx-lesson/sample-episode-rst/
We should all take a look and make sure it looks as we expect a typical page to look, and adopt any conventions early.

Examples:

• embed solution admonition block within the exercise block itself
• conventions for exercise labeling/titles