cluster/coredns: add cluster fqdn top level domain

This means that in addition to services being discoverable the 'classic'
way:

    <svcname>.<namespace>.svc.cluster.local

They are now discoverable as:

    <svcname>.<namespace>.svc.<fqdn>

For instance, on k0 you can now internally resolve:

    $ kubectl run --rm -it foo --image=nixery.dev/shell/dnsutils bash
    bash-4.4# dig +short coffee-svc.default.svc.k0.hswaw.net
    10.10.12.192

Change-Id: Ie6875b54ed6358f30f888ca0cd96e011520ace20
2 files changed