www/mod_dnssd: Deprecate and set expiration date
Upstream has been abandoned since the 0.6 release in 2008; the download
directory has never carried anything newer and the port is only kept
building by local patches.
MFH: 2026Q3
Sponsored by: Netzkommune GmbH
(cherry picked from commit 741389d46352a5c1545fec77871d76c06597c782)