Refactor to leverage Headless Chrome over PhantomJS

[gingeleski]

At the time we first wrote this (mid-2017), the field of headless browsing was surveyed to determine what we'd base the tool on. Headless Chrome was not yet mature enough to meet our needs and we focused on PhantomJS.

Now I believe that's no longer the case. It would be preferable for the tool to be based primarily on Headless Chrome.

This is something I intend to tackle in my fork during (currently sparse) downtime.

Related resources, for my reference and anyone interested in Headless Chrome:

• Headless Chromium
• Github GoogleChrome/puppeteer
• Why and how to use Headless Chrome for Ember testing
• How Gitlab switched to Headless Chrome for testing
• Tools for Web Developers - Puppeteer