sysutils/munin-{master,node}: change cron job install
Don't rely on directly calling crontab(1) to install the cron job, use
the etc/cron.d directory for which we've had support for a while. This
fixes installing munin-master using pkg -r as crontab(1) installed the
cron job on the host system not in the specified alternative root
otherwise.
Completely remove pkg-install, that also removes the automatic migration
for newsyslog files after src revision r340318 it's been 4 years and a
bit.
Leave the pkg-deinstall script for a while to make sure that the
automatically installed cron jobs via crontab(1) are removed.
PR: 258072
Reported by: Tassilo Philipp <tphilipp@potion-studios.com>
Tested by: Tassilo Philipp <tphilipp@potion-studios.com>