Bugs in API for redacting attachments

The management interface provides a way to redact, hide or delete an email.
However it's possible that the information that needs to be processed is in an attachment.
There ought to be a way to hide or delete these as well.

Note that attachments may be shared between emails

Start by tracing the management interface API for redacting, hiding, or deleting emails and then follow how attachments are represented and shared between emails. Done means the API can hide or delete the requested attachment while handling shared attachments without affecting unintended emails.

Written by the indexing model from the issue text.