Some systems don't have a hardware real time clock and don't know the time
after bootin. An obvious soulution for this is to use time from an ntp
server. Unfortunately that requires domain name resolution, which resolvers
like unbound won't do for us, if the DNSSEC certificates aren't valid, which
they aren't if we start out with a time around 1970-1-1.
The "software clock" service tries to provide a workaround by restoring a
reasonably valid time from a backup file during boot, which we update when
shuting down. If we wan't a more correct time, we have to update it from
NTP in between.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
