Add YAML formatting (prettier)

[jrbourbeau]

Closes #364. I broke this into two commits, one which adds the pre-commit hook, and one which applies the formatting, to hopefully make reviewing a little easier.

cc @mfisher87 @betolink @jhkennedy

[github-actions]

👈 Launch a binder notebook on this branch for commit 111ed7f

I will automatically update this comment whenever this PR is modified

[MattF-NSIDC]

I broke this into two commits, one which adds the pre-commit hook, and one which applies the formatting, to hopefully make reviewing a little easier.

💯 I love this approach, because it means later we can use .git-blame-ignore-revs to exclude massive formatting changes from blame view.

EDIT: https://github.blog/changelog/2022-03-24-ignore-commits-in-the-blame-view-beta/

[MattF-NSIDC]

Beautiful 🤌