Email gateway integration

[sergiimk]

Scope

• No mass emails yet or cohorts (<10 emails at a time)
• Emails are fire-and-forget / best effort
• Every account should have an email (including predefined accounts)
• kamu and other predefined accounts will send to a google group
  • use plus notation to create unique emails

Tasks

• Select an email gateway service (e.g. Sendgrid)
• Create email gateway service with implementation for the chosen tech
• Create a set of event handlers that listens to event bus events and sends emails
  • Handlers will be parameterized with different email templates
  • Create top-level graphic template for email (branding, social links, etc.)
• Setup initial reactions to pipeline failures