Instead of having different ESLint configuration files in each
directory which don't seem to inherit the configuration correctly, this
will add `overrides` in the root file.
This wil remove the discrepancy between the files on which ESLint is run
when `lint-staged` is used and the files that are checked using
`npm run lint` and `npm run format`.
It will now also include the `.storybook` directory which was previously
excluded from the ESLint configuration.