* Job object can now control the output and generate K:V output for
notification types that can support it
* Notifications store the body as json/dict now to encode more
information
* Notification Type can further compose the message based on what is
sensible for the notification type
* This will also allow customizing the message template in the future
* All notification types use sane defaults for the level of detail now
* Implement concrete Notification model for notification runs
* Implement NotificationTemplate and Notification serializers and views
* Implement ancillary views
* Implement NotificationTemplate trigger m2m fields on all job templates
via a fields mixin
* Link NotificationTemplates with an org
* Link notifications with the activity stream
* Implement Notification celery tasks
* Extend Backend field parameters to identify sender and receiver as
parameters needed by the message and not the backend itself
* Updates to backends to better fit the django email backend model as it
relates to Messages
* Implement success job chain task + notifications
* Implement notifications in error job chain task
* A basic NotificationTemplate model class with early notification type
definitions
* Initial implementations of the Email, Slack, and Twilio Notification
backends using the Django email backend system
* Some dependencies thereof
