ZTS: Use FreeBSD cloudinit images

FreeBSD provides CI-IMAGES since some time. These images are
based on nuageinit, which does not support fqdn and sudo for
example. So we need currently some workarounds to get it
working.

The FreeBSD images will be more compatible with cloud-init in
some near future. Then we can remove the workaround things.

These versions are used for testing:

• freebsd13-4r (RELEASE)
• freebsd14-3s (STABLE)
• freebsd15-0c (CURRENT)

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes #17462