Right now we will just send SIGTERM to all processes in the jail
after 5 minutes of wallclock. After an additional 10 seconds we
send SIGKILL if necessary.

Also added -N option to start up (-C) a standalone jail without
and resource limits.

Note that this won't work on ops yet as we have not enabled the
kernel racct mechanism in /boot/loader.conf. On next reboot it
should start being used.