Update about.md
Update about.md

add what is where

Former-commit-id: 33e9244e061579274e5b801ca8cf08bfe568849e [formerly 5de1c29b5877f5ff49474b0306f1751b547187a6]
Former-commit-id: 38673b4713938b9f485202acdf49c88abdc9c595
LibraryCarpentry/librarycarpentry.github.io,LibraryCarpentry/librarycarpentry.github.io,LibraryCarpentry/librarycarpentry.github.io