Provide a Diagnostics.file example for kubeadm bootstrapped clusters

[moondev]

It would be helpful in the documentation to provide a fully featured example for kubeadm bootstrapped clusters.

This would be a stable target as well as allow one to get started quickly. Once globbing is available in https://github.com/vmware-tanzu/crash-diagnostics/issues/16 this should be easier to create, as most of this revolves around the fact that containerized components such as kube-apiserver do not have a stable log path like /var/log/kube-apiserver.log

[vladimirvivien]

@moondev awesome, thanks for the suggestion. I am working to catch up with my backlog.