Prepare deployment to Vagrant (toy-production) environment

* Use airbrake instead of ExceptionNotifier
* Bump therubyracer because of https://github.com/alphagov/static/pull/275
* Add vagrant deployment scripts
* Set GOVUK_APP_DOMAIN
* End Plek and GOVUK_APP_DOMAIN madness
* Do not deliver with ses which does not exist any more
* Notify airbrake only if exception is present
* Deploy from bis branch