Kubeadm: remove klog and util/errors dependencies from the kubeadm system-validators

[neolit123]

/kind cleanup
/priority important-longterm

as discussed on slack the validators under k/k/cmd/kubeadm/app/utils/system should drop certain dependencies:

mini-guide:

• clone kubernetes/kubernetes
• modify the package here:
  https://github.com/kubernetes/kubernetes/tree/master/cmd/kubeadm/app/util/system
• to not use klog and the errors package as described by these messages:

for the validation utils repo, I'd strongly recommend dropping the k8s.io/klog and k8s.io/apimachinery/pkg/util/errors dependencies

the main things I see you might consider changing:
• the places you are logging messages should potentially be returned to the caller as warning/info data (that they could log if desired)
• the places you aggregate multiple errors into a single error (using the apimachinery method), you might consider returning []error (or defining your own type AggregateError []error type that implements Error() string and Errors() []error to allow getting at the underlying errors)

see the conversation history on slack for more detail:

https://kubernetes.slack.com/archives/C2C40FMNF/p1566414724378100?thread_ts=1566411984.368700&cid=C2C40FMNF

https://kubernetes.slack.com/archives/C2C40FMNF/p1566415427380800?thread_ts=1566411984.368700&cid=C2C40FMNF

• send PR

[Klaven]

I can do this.
/assign

[neolit123]

punting to 1.17 as we are in code freeze.

[Klaven]

@neolit123 I must have screwed up the reference as this has been merged and this issue can be closed now.

[neolit123]

@Klaven
thanks, i guess the next step is to decide on the versioning of the validators repo and move them.

cc @yastij