As a user I can receive notification scheduled reports by email

Today, a user can receive a scheduled notification for deliverable items state updates.

Tomorrow, a user can receive scheduled notifications that report events and activity:

• actions that happen on a favorited object:
• Modification/creation (by type of fave item):
• Project: (based on project members) status change, new del set, deliverable change, new source, new background, new post
• Deliverable set: deliverable changes, new post
• Deliverable: state changes, new post
• Source container: source added
• background container: background doc added

Email template: TBD

How:

• Use of the same existing KVS for cron notifications
• Enrich the object to store/fetch/invalidate to respond to the requested email content (TBD)