Email integration

[AllanEngland]

It would be useful if Polaris could send emails to users at predetermined points in the workflow. For example when a proposal has been accepted or rejected.

The exact time an email is sent may have to configured per TAC depending on their process, and the email may have to be templated by the observatory/TAC to use their branding or terminology. I understand that NorthStar sends emails, but I don't know to what degree these are configurable.

I believe a core email feature would reside in the API project, however I don't know to what degree the GUI should be involved for configuring or triggering the emails.