add prettier, eslint and stylelint to project

[eddyloewen]

[eddyloewen]

I've added the libraries. The only remaining thing to do here is to add a github action to automatically run linting on merge requests

[eddyloewen]

Also we removed .json from lint-staged because it was crashing the linter...
Also add json when linting manually via yarn run

[eddyloewen]

Closing as out of scope. Prettier and ESLint are in place (package.json + lint-staged + Husky pre-commit). Stylelint was not adopted because component styles are CSS-in-JS tagged-template literals (*.style.js), not standalone CSS files, so a CSS linter no longer fits the project shape.