Create a separate SMTPD service for receiving email for local delivery

[scanner]

Using postmark or an equivalent service to receive emails is okay. However postmark has no way to refuse a received email if we do not actually have an account to receive that email. We just drop it on the floor.

Also postmark's spam assassin seems a bit weak. We have to set a level of 2 for most obvious spam to be denied. So we want to receive emails ourselves. We will use a separate demon for this, listening on a separate interface.

• It will only accept email for domains we are hosting.
• It will only accept email for email addresses that exist on our service
  • Maybe we should have a separate flag on the email account model that indicates whether the address even accepts email. "active" flag lets that account send email.
• should have hooks for spam filtering on receiving ip addr, domain, email address, and email content.
• should have hook for denying a sending domain, ip addr, email address that has failed more than times in amount of time. Let us say 5 times in an hour - use a similar class to the authenticator for aiosmtpd

[scanner]

In orde to roll this out on the same server but binding to different interfaces add variables to the .env that specify the interfaces to bind to. host from the asyncio.create_server accepts either a string or list of strings that are IP address interfaces to bind to.

So we need an env var for the relay/user aiosmtpd and one for the local delivery aiosmtped.