Configure notifications recipients

[raaaahman]

trafficstars

Notifications could be configured to be sent or not to specific recipients (users) or broader categories (roles).

This could be done by passing a configured Recipient_Factory to the Notification_Factory responsible for instantiating the given notifications.

[EdithAllison]

I can see why this would be nice, but I don't know how it would work in reality, as plugins using the API won't know which users and roles are active.