* Add AMP First example
The sample demonstrates how to build an AMP First Site with AMP. If
follows all the best-practices recommended by Lighthouse and will
result in a fully-qualified PWA.
Live demo of the page: https://my-next-app.sebastianbenz.now.sh/#development=1
* small improvements to AmpScript and AmpState
* remove gitignore
* Update example
* Move styles down in Layout
* Apply lint fix and tweak prop-types
* Add warning for host header usage
