Add smoke test for user flows

[connorjclark]

First idea is to add a callback/runner/idk property to smoke test definition that takes a page and flow and runs a user flow for that.

Adam points out it may be too complicated to add this to smokehouse, and may be better to just have jest tests.

[adamraine]

We discussed different ways to add smoke tests:

1. Create an entirely new smoke runner for user flows
2. Modify smokehouse to accept 2 different types of tests (single navigation and user flow)
3. Continue to user unit tests to run user flows in the scenarios directory

We aren't super thrilled about option 1 since we would have to maintain 2 smoke runners.

I'm coming around to Connor's original idea to add a callback fn to smoke tests. It might help to increase our flow e2e test coverage without as much mocha boilerplate.