Configure account confirmation via SES

[jayhill]

1. Set up AWS SES.
2. Verify ownership of your email domain (zipcase.org) by adding DNS TXT records provided by SES to Route 53.
3. SES confirms your domain is verified.
4. Link SES to Cognito via Terraform:

resource "aws_cognito_user_pool" "zipcase_user_pool" {
  name = "zipcase-user-pool"
  
  email_configuration {
    email_sending_account = "DEVELOPER"
    source_arn            = aws_ses_email_identity.zipcase.arn
    from_email_address    = "no-reply@zipcase.org"
  }

  verification_message_template {
    default_email_option = "CONFIRM_WITH_CODE"
    email_subject        = "Welcome to ZipCase! Verify your email."
    email_message        = "Your ZipCase verification code is {####}."
  }
}

resource "aws_ses_email_identity" "zipcase" {
  email = "no-reply@zipcase.org"
}