Support email notification for content approval

There are two aspects to this

1) Notify a group of people when content is awaiting approval

• Normally a core team will be defined, who don't require approval being given, when this content is submitted, no email should be sent
• The group who are notified should be configurable, and ideally offer the option to send to an email list

2) Notify the original contributor of the content once it is approved

• Providing thanks is essential for community building