allow to pass options to dnsmasq service

There were request to pass parameters to dnsmasq container in kube-dns
addon.

This PR adds variable master.addons.dns.dnsmasq (dict) which can be
used to pass options to dnsmasq container. Defaults are configured in
metadata.

Change-Id: If072e31a8a1cde4c984c67373ad74d45204619b0
3 files changed