chore: format all files

[mdjermanovic]

This PR:

• Checks in formatted versions of all files in the repo (I ran npm run fmt) so that unrelated formatting changes no longer appear in PRs.
• Adds Verify Files CI job that checks if all files are lint-free (eslint) and properly formatted (prettier).
• Adds a lint-staged task to format non-js files.

Question: I assumed we want to format all files that prettier knows to handle. Are there some files we'd like to ignore or format differently? I only ignored CHANGELOG.md files because those are autogenerated.

[nzakas]

Question: I assumed we want to format all files that prettier knows to handle. Are there some files we'd like to ignore or format differently?

I think just CHANGELOG.md we should leave alone. Otherwise, I'm :+1: to formatting everything. We can always adjust later if we don't like something.