Add Prettier and/or .editorconfig for formatting

[dylanirlbeck]

We have a few JS files in the project with no associated formater/linter, so let's add one.

[JakubMarkiewicz]

Would just simple

{
    "trailingComma": "es5",
    "tabWidth": 4,
    "semi": false,
    "singleQuote": true
}

with ignoring

*.json
*.css
*.bs.js
*.yml
*.md

and workflow

      - name: format js files
        run: |
          npx prettier --write .
          git add "*.js"

Be fine for you? I'm not sure about the workflow, never used it before

[dylanirlbeck]

That should work! My intention is just to format the JS files in workflow/ and js/. If you open a PR and/or test locally that'd be awesome.