LogExpireInterval, StatsLogExpireInterval, CrashExpireInterval, MinDiskSpace
and MailHostUpDown are only acted on by ZeekControl's 'cron' command, which
nothing ever ran, so setting them in SOC had no effect.
Track those five in /opt/so/state/zeek/zeekctl_cron_settings and trigger the
cron run off that file, so unrelated edits like CompressLogs don't fire it.
Runs as the zeek user to avoid root-owned files under /nsm/zeek, with
--no-watch so the crashed-node watchdog doesn't race the container restart.
Josh Patterson
d87deb6671