This is a complete rewrite of time sync process.
Now the time sync process starts early at boot time, and it adapts to
configuration changes:
* before config is available, `pool.ntp.org` is used
* once config is available, configured time servers are used
Controller updates same time sync resource as other controllers had
dependency on, so they have a chance to wait for the time sync event.
Talos services which depend on time now wait on same resource instead of
waiting on timed health.
New features:
* time sync now sticks to the particular time server unless there's an
error from that server, and server is changed in that case, this
improves time sync accuracy
* time sync acts on config changes immediately, so it's possible to
reconfigure time sync at any time
* there's a new 'epoch' field in time sync resources which allows
time-dependent controllers to regenerate certs when there's a big enough
jump in time
Features to implement later:
* apid shouldn't depend on timed, it should be started early and it
should regenerate certs on time jump
* trustd should be updated in same way
Signed-off-by: Andrey Smirnov <smirnov.andrey@gmail.com>