Add new web origin trial token for WebVR

[gfodor]

The current one expires 7/12

Origin: https://hubs.mozilla.com
Expires: 2018-08-21 (we'll send you a reminder to renew before this date)
Trial Token:
AmTuFlYFGJ4KEbPVE20U0qoWZI3NZuaO8bjjcQvQI4OvDVC4Iyun5gkD8lwtNbrEzh617m5nig0+8QC+Pz6powYAAABVeyJvcmlnaW4iOiJodHRwczovL2h1YnMubW96aWxsYS5jb206NDQzIiwiZmVhdHVyZSI6IldlYlZSMS4xTTYyIiwiZXhwaXJ5IjoxNTM0ODg3ODE1fQ==

To add this token to your site, add the following tag to the of every page that will use the feature:

[gfodor]

<!-- Origin Trial Token, feature = WebVR (For Chrome M62+), origin = https://hubs.mozilla.com, expires = 2018-08-21 -->
<meta http-equiv="origin-trial" data-feature="WebVR (For Chrome M62+)" data-expires="2018-08-21" content="AmTuFlYFGJ4KEbPVE20U0qoWZI3NZuaO8bjjcQvQI4OvDVC4Iyun5gkD8lwtNbrEzh617m5nig0+8QC+Pz6powYAAABVeyJvcmlnaW4iOiJodHRwczovL2h1YnMubW96aWxsYS5jb206NDQzIiwiZmVhdHVyZSI6IldlYlZSMS4xTTYyIiwiZXhwaXJ5IjoxNTM0ODg3ODE1fQ=="> 

[mqp]

Updated in #472.