chore(lint): lint all files

[lukekarrys]

This change consolidates all lint rules and paths to the root of the repo, and runs them as part of the lint workflow.

There were only a few manual changes to make, so I opted to make it lint everything, meaning eslint for all *.js files and prettier for all file types it knows about by default. I can easily revert and ignore any files that shouldn't be linted, but as a first pass it was easier to lint everything.

[iansu]

Nice! Thanks for doing this.