Currently, the only supported options for processing inbound mail are Mailgun, SendGrid and Local MTA. We are using AWS Simple Email Service (SES) for outbound mail and I would like to also use SES for inbound mail processing as well.
There currently exists `/mail/mailgun/` and `/mail/sendgrid/` endpoints that Mailgun and SendGrid can POST emails to. I was wondering if the upstream would be open to accepting the contribution of a `/mail/ses/` endpoint to facilitate the use of SES for inbound email? SES doesn't directly support the delivery of mail via POSTing to a HTTP endpoint, but it does allow publishing to an SNS topic (which itself can be used to POST to a HTTP/HTTPS endpoint)
If the upstream doesn't want to accept an SES integration, perhaps the upstream would instead allow for some modifications to `PhabricatorMetaMTAApplication` to allow third-party extensions to expose custom endpoints under a subpath, such as `/mail/inbound/{mailgun,sendgrid,ses}/`.