Adds an "Attachment" condition field (is present / of type <ext>) backed by
the RFC 5703 Sieve mime extension, matching the filename in both
Content-Disposition and Content-Type headers so real-world senders that only
put the name in Content-Type (Microsoft SMTPSVC, etc.) are caught. Users type
extensions (pdf, doc) not MIME types.
Also makes each text condition accept comma-separated multiple values emitted
as a Sieve string list (OR within the condition), so "(domain1 OR domain2)
AND attachment pdf/xml" is expressible in one rule. value is now string |
string[] (single-value rules stay strings -> backward compatible). New filter
locale keys in all 17 locales.
