Update DNS Instructions

This is related to https://github.com/kubernetes/kops/issues/1227 but more specific.

This section describes hosting a subdomain in route53, while having the domains root Nameservers hosted in GoDaddy. https://github.com/kubernetes/kops/blob/master/docs/aws.md#scenario-3-subdomain-for-clusters-in-route53-leaving-the-domain-at-another-registrar

I believe that GoDaddy has changed there service / user interface where they no longer allow for Route53 Nameservers to be used for just a subdomain.

For instance:

Domain example.com - Registered with GoDaddy
Subdomain k8s.example.com - Subdomain setup in Route53
Cluster cluster.k8s.example.com - cluster name

GoDaddy allows for Route53 to manage example.com, but I cannot find documentation or the page on how to setup GoDaddy to allow the Route53 nameservers for k8s.example.com.

Can someone confirm this for me, and then the docs need to be updated.

Start with docs/aws.md, especially the “Scenario 3: Subdomain for clusters in Route53, leaving the domain at another registrar” section, and review related issue #1227. Verify the current GoDaddy and Route53 setup for delegating k8s.example.com, then update the instructions so the documented procedure matches the supported workflow.

Written by the indexing model from the issue text.