Added a Testem configuration that launches a Qunit page with an iFrame that builds and loads our mock-dev page and can interact with it and run tests on it.
Wrote a simple test that accepts the terms and conditions and transitions to the next page.
I am not doing any fancy redux-hooks for the async waiting, I've simply added a `tests/integration/helpers.js` file with a `wait()` function that returns a promise that should wait long enough.
Long term we should hook into the app lifecycle by some means for testing, so we only wait the right amount of time, and wait long enough for slower processes to complete, but this may work for the time being, just enough to run some basic automated browser tests.
