enable ntpd by default at install time. We use pools and a reliable
constraint to keep them in check. in the worst case of being on a
dark net, nothing changes.
this is being enabled by default to allow gathering of more operational
information from users. and if the operational heuristics in ntpd can be
suitable refined, this may stay the default into the future. if not, ntpd
will become even more awesome along the way.
with reyk rpe