chore: Add ESLint Prettier config

[nschonni]

@jeffwilcox, this might be too early in your refactoring work to add, but you can always copy the .eslintrc.js, .prettierrc.json, and package.json changes when you ready, then run the npm run fix on you cleanup branch

[nschonni]

@jeffwilcox did you want me to try and fix up the conflicts or just close it?

[jeffwilcox]

@nschonni I appreciate the offer!

I think if we could keep this PR open for now, it would help... I think we're going to want to take the prettier config and get it running internally first (we have a lot of Microsoft-specific code we hold back in specific directories right now), and then bring it forward here.

If you had a few minutes to submit just the actual config changes, but not touching all the random files, I'd be happy to merge that pull request once we're ready, vs this PR, if that works?

[nschonni]

@jeffwilcox I rebased out the changes from npm run fix (and possibly some manual cleanups). Backed that up to https://github.com/nschonni/opensource-portal/tree/eslint-prettier-old branch in case there was anything useful in the manual cleanups

[jeffwilcox]

Thank you!

[nschonni]

Just added the call back to linting in the CI in a separate commit, so that the current issues will get shown with the setup-node problem matcher