Create an email-audit system that's viewable on django admin

[SSPJ]

Acceptance criteria:

• all email messages are logged
• messages are logged to the cloud.gov stack
• email address and subject line are captured
• logs are viewable from the admin interface

[h-m-f-t]

Leaving a note in modern times: We're currently Bcc'ing most user emails to [email protected]. This provides an easy way for analysts to see that an email was sent, but more importantly gives them a chance to follow up on a given action (like various "action needed" emails).

But this is pretty annoying to manage in an inbox! It would be nicer to log as the A/Cs above describe and show that log in a domain (and/or portfolio?)'s activity log, and potentially allow for manual (/automated) follow-ups.

[abroddrick]

Assigning this to myself to refine later today based on the discussion had today with Liz

[katypies]

While not strictly required for the Org Model notifications, we're going to be potentially increasing the number of emails being sent, especially to add people to portfolios. Being able to see the logs of those emails and/or details about them will make supporting the Org Model much better.