Chore/modern ember tests

[tomwayson]

Test like this: https://dockyard.com/blog/2018/01/11/modern-ember-testing.

I had a hard time converting this.

• the codemod didn't work
• I had to add the babel polyfill just to get past regeneratorRuntime undefined error (feels like there should be a better way to deal w/ that)
• I could never get fetch-mock to work, so I had to replace it w/ sinon stubs (which I prefer anyway)

Maybe all of that would have worked better if I had done this after upgrading to Ember 3?

Also, removes all use of jQuery and updates lint config to treat future use as an error.