Had to add an email attribute to users to store their email to send the
notification. Will only send it for user rooms since they are the only
ones we know who to notify.
It almost works with webhooks now. Still TODO is:
* Remove the hook after the recording is published
* To process the publish_ended event from the webhooks either the webhook
needs to include the metadata (currently it doesn't) or GreenLight has
find out the meeting token without reading it from the metadata.
