FEATURE: Add email_encoded parameter to accept inbound base64 encoded emails (PR #12947)

We have found when receiving and posting inbound emails to the handle_mail route, it is better to POST the payload as a base64 encoded string to avoid strange encoding issues. This introduces a new route and maintains the legacy route. Eventually the old route will be dropped and the new one will be the only way to handle_mail.

GitHub

The title of this pull request changed from “FEATURE: Add handle_mail_encoded route to accept inbound base64 encoded emails” to "FEATURE: Add email_encoded parameter to accept inbound base64 encoded emails