Allow running in headful mode

[dcurletti]

Great docker setup here, but was hoping I'd be able to run this in headful mode out of the box (headless: false).

[dcurletti]

https://stackoverflow.com/questions/51667599/issue-in-executing-puppeteer-in-headful-mode-in-docker

https://github.com/nsourov/Puppeteer-with-xvfb