Create introduction to git class

[jgarst]

There is a lot of need, and also many public resources on the subject. We need to answer.

1. What is the end goal of a 1 hour class?
2. How will people without git installed follow along?
3. What are calibrating questions? What is a good final project?

Julia Evans exersizes might be a good place to start.
https://jvns.ca/blog/2019/08/30/git-exercises--navigate-a-repository/