Transpiling client.js to target browsers using webpack

[schrepfler]

TODO:

• Make sure all of the significant new logic is covered by tests
  No new logic.
• Rebase your changes on master so that they can be merged easily
• Make sure all tests and linter rules pass
• Update CHANGELOG.md with your change

[schrepfler]

Once we get this sorted, are you open to do the similar thing with the other needed libs? (my guess apollo subscriptions and probably graphql? @Urigo

[Urigo]

Thanks @schrepfler ! great work. I will test and verify it soon.