- Use the chronyc onoffline command to update state of all sources
  per current routing configuration
- Don't ignore the "ifupdate" action
- Add NTP servers from DHCP for the interface that went up instead of
  the wan4+wan6 interfaces
- Save the servers to files loaded by the sourcedir directive to not
  lose them when chronyd is restarted, and remove them when the
  interface goes down

Signed-off-by: Miroslav Lichvar <mlichvar0@gmail.com>

- fix the init script to read the right config
- rework the init script to allow reusing its code in the hotplug script
- find wan interfaces in the hotplug script instead of using hardcoded
  name and set the online/offline status separately for IPv4/IPv6
- allow NTP access on interfaces that are configured after chronyd start
- add NTP servers obtained from DHCP, options are specified in a new
  dhcp_ntp_server config section
- start chronyd before the network service, include a patch to always
  have IP_FREEBIND defined, which seems to be missing with uclibc

Signed-off-by: Miroslav Lichvar <mlichvar0@gmail.com>

Support for authentication with command key was replaced with
communication over Unix domain socket.

Signed-off-by: Miroslav Lichvar <mlichvar0@gmail.com>

Signed-off-by: Miroslav Lichvar <mlichvar0@gmail.com>