Cypress UI testing & verify template tests

[jmulcahey-twilio]

Description

Adds the Cypress automated browser testing framework, an npm start command that starts a development server to host the templates with Cypress tests, and includes UI tests for the verify function template.

Checklist

• [x] I ran npm test locally and it passed without errors.
• [x] I acknowledge that all my contributions will be made under the project's license.

Related issues

[andreasonny83]

It looks promising. Does this mean all the Cypress tests will live inside the root level Cypress folder rather than inside each individual project?

[andreasonny83]

@jmulcahey-twilio, @dkundel is there any progress on this PR?