Convert @zooniverse/async-states to ES6

[eatyourgreens]

Switch @zooniverse/async-states from require to static import and export. Publish the package as ESM, not CommonJS.

Tests fail in consuming packages, because of #3779.

Package

lib-async-states

How to Review

Build and run both the project app and the content pages app. Both apps should be unchanged.

Checklist

PR Creator - Please cater the checklist to fit the review needed for your code changes.
PR Reviewer - Use the checklist during your review. Each point should be checkmarked or discussed before PR approval.

General

• Tests are passing locally and on Github
• Documentation is up to date and changelog has been updated if appropriate
• You can yarn panic && yarn bootstrap or docker-compose up --build and FEM works as expected
• FEM works in all major desktop browsers: Firefox, Chrome, Edge, Safari (Use Browserstack account as needed)
• FEM works in a mobile browser

General UX

Example Staging Project: i-fancy-cats

• All pages of a FEM project load: Home Page, Classify Page, and About Pages
• Can submit a classification
• Can sign-in and sign-out
• The component is accessible
  • Can be used with a screen reader BBC guide to VoiceOver
  • Can be used from the keyboard WebAIM guide to keyboard testing
  • It is passing accessibility checks in the storybook

Refactoring

• The PR creator has described the reason for refactoring
• The refactored component(s) continue to work as expected

[eatyourgreens]

@zooniverse/async-states is a single JS file and tests, so it seems like a good candidate to try running the Mocha tests with export default rather than module.exports =.

[eatyourgreens]

Tests replace import with require, which fails with this error:

Error [ERR_REQUIRE_ESM]: require() of ES Module 
/home/runner/work/front-end-monorepo/front-end-monorepo/packages/lib-async-states/src/async-states.js 
from 
/home/runner/work/front-end-monorepo/front-end-monorepo/packages/app-project/stores/Store.js 
not supported.
Instead change the require of async-states.js in 
/home/runner/work/front-end-monorepo/front-end-monorepo/packages/app-project/stores/Store.js 
to a dynamic import() which is available in all CommonJS modules.