Native ES modules

[matt-allan]

This PR converts the Radiance repo over to native ES modules. Every supported version of Node supports native ES modules so we don't need to use Common JS anymore.

By default every .js file will now be parsed as an ES module. If you need the file to be parsed as a CommonJS module (i.e. because you're using a package that only supports CJS) you can use the .cjs extension.

We can't drop the CommonJS bundle yet because the @emotion/styled package is not fully setup for ES modules yet and breaks when you try to import @emotion/styled/base. You can repro it with this script:

import { Button } from './dist/bundle-es/index.js';

console.log(Button);

$ node testing.js
node:internal/process/esm_loader:74
    internalBinding('errors').triggerUncaughtException(
                              ^

Error [ERR_UNSUPPORTED_DIR_IMPORT]: Directory import '/Users/matt/code/radiance-ui/node_modules/@emotion/styled/base' is not supported resolving ES modules imported from /Users/matt/code/radiance-ui/dist/bundle-es/shared-components/typography/index.js
Did you mean to import @emotion/styled/base/dist/emotion-styled-base.cjs.js?

In the interim if you need to use Radiance components from node you still have to use Common JS:

const radiance = require('./dist/bundle.cjs');

const { Button } = radiance;

console.log(Button);

$ node testing.cjs
[Function: Button] {
  Container: <ref *1> [Function (anonymous)] {
    displayName: 'ButtonContainer',
    defaultProps: undefined,
    __emotion_real: [Circular *1],
    __emotion_base: 'div',
    __emotion_styles: [
      'label:ButtonContainer;',
   // ...

[matt-allan]

Opened emotion-js/emotion#2413 for the Emotion issue. I don't think we can fix it on our end.

[matt-allan]

Going to close this until we are unblocked by Emotion.