Automatic merge from submit-queue
Add --apiserver-advertise-address option to kubeadm alpha phase certs…
**What this PR does / why we need it**:
`kubeadm alpha phase certs` command currently does not support `--apiserver-advertise-address` options, and certificates by default are linked to the bind address of the machine where the kubeadm command is run. This behaviour is not adequate f.i. for use cases where you are using `kubeadm alpha phase certs` for an HA deployments or for use cases where you generate certificates on a machine different that the master.
The PR adds support for `--apiserver-advertise-address` to `kubeadm alpha phase certs`, with the following behaviour:
- if `--apiserver-advertise-address` is specified and valid, certificates are linked to the given IP
- if `--apiserver-advertise-address` is specified but not valid, the given ip is not valid an error is given
**Special notes for your reviewer**:
Implementation follow the track already in place for other flags (with validation, but no tests).
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