Investigate better email sending

Investigate better ways of sending emails for notifications, reports, etc.

Current issues it would be nice to overcome:

• emails are only currently sent from the frontend, but then that means each frontend has to implement sending emails
• emails are flagged as spam, not sure why
• it would be nice if each gateway could send emails from their own domain/email address (might also help the spam situation). To facilitate that would it make sense to integrate with services like SendGrid?
• we would like to send reports over email, but for reasons mentioned above, today we could only do that from the web client, but that seems inappropriate