Add instructions on navigating Stanford GitHub

[malcolmbarrett]

Since you need to auth a lot more

Mostly, I think continue to recommend gh auth login but also links to docs on SSH etc

[malcolmbarrett]

note to self: On Sherlock I bumped into auth issues and need to do gh auth login -> set up new ssh -> configure ssh key to auth with Stanford single sign in. I did not need to do this locally or on Nero, but it is not clear to me if there is something inherently different about Sherlock