net-mgmt/cacti: Update to 1.2.11

Also change maintainer to submitter. Thanks for maintaining this port
for the last 5 years Dan, and for stepping up to the plate Michael!

Changes this release:

https://github.com/Cacti/cacti/blob/release/1.2.11/CHANGELOG

PR: 245468
Submitted by: Michael Muenz <m.muenz@gmail.com>
Approved by: Daniel Austin <freebsd-ports@dan.me.uk> (maintainer)