If we set --external-hostname, then the api server does not look
in the CloudProviderOptions.DefaultExternalHost method. While we
are at it, let's log an info message, so if there is a failure
the operator gets a hint that they can use --external-hostname
to bypass the lookup in the cloud provider. This will enable us
to set the CLOUD_PROVIDER to openstack for example and not have to
really run api server inside a openstack vm.
Automatic merge from submit-queue (batch tested with PRs 47038, 47105)
extending DefaultExternalHost for any registred cloud provider
**What this PR does / why we need it**: this PR enables DefaultExternalHost to work with any registered cloud provider.
**Which issue this PR fixes** : fixes#46567
**Special notes for your reviewer**:
**Release note**:
```release-note
When determining the default external host of the kube apiserver, any configured cloud provider is now consulted
```