Set up cypress tests for Formstack

### As a website user, I want forms to work so that I can fill out forms.

### As a developer, I want to be informed when form styles break so that I can fix them.

**Is your feature request related to a problem? Please describe.**
We made some fancy style tweaks to our forms. I'd like to be informed when they break if something gets updated on Formstack's side without our knowledge.

**Describe the solution you'd like**
An automated test suite to make sure our embedded forms still look good at every breakpoint. We'll have it run on a cron job daily.

**Describe alternatives you've considered**
Hoping that things won't break (current testing strategy).