Site-wide Announcement Notification

@statico for review

@WHiT3R4bBiT This is pending copy for emails and on-site messages

The email will only be triggered if the notification is created via
`/announcements/announcement/create` and not via admin interface.


The reason that they exist is that the fit into the framework of the django-notifications. This is the expected format for notifications so removing these templates would probably cause more future confusion than leaving them in this standardized format.
What do you think?