See: https://github.com/avivkeller/learn
See: https://aviv.sh/learn (Note: This is set-up to run at learn.nodejs.org, and, as such, the sidebar does not work, since it's used at aviv.sh/learn)

Closes nodejs/nodejs.org#8612
Closes? nodejs/learn#38

cc @nodejs/nodejs-website