* feat(ntp): use ntp server from dhcp info
* feat(ntp): use ntp server from dhcp info
* feat(ntp): add delay between time sync attempts
* chore(ntp): more logging
This commit fixesjetkvm/kvm#12 by disabling the udhcpc client when the
link goes down, it then removes all the active IPv4 addresses from the
deivce.
Once the link comes back up, it re-activates the udhcpc client so it can
fetch a new IPv4 address for the device.
This doesn't make any changes to the IPv6 side of things yet.