Implement some kind ordering in the startup of package script daemons.

Implement some kind ordering in the startup of package script daemons.
'rcctl order ...' will prepend the daemon(s) given as argument to the
pkg_scripts line (it can be all daemons, some, or just one).
Without argument, it'll display the current order.

While here, drop a couple of examples from the man page to only leave
the most interesting one.

ok schwarze@ rpe@ (with tweaks) jasper@ robert@ sthen@