dynamically get the nodeport host

[yahoon]

Greetings,

This is an update to the example doc of Using Kubevirt. The purpose is to dynamically get the NodePort host to replace the hardcoded hostname that is used for the VM SSH connection.

The problem we solved
By fetching the hostname dynamically, we avoid using a pre-defined host for the VM SSH connection, that will reduce the the potential failures by the connection problem with the host. In this update, the hostname for the SSH connection is fetched dynamically, which is the K8S node where the VM is running.

I get this tested in our environment with @jangel97

Thanks.

[github-actions]

Label error. Requires exactly 1 of: bug, enhancement, major, minor, patch, skip-changelog. Found:

[yahoon]

I don't have the permission to add labels to this PR. Please help add docs, enhancement to it, thanks.

BTW, @jangel97 is the original author of this guide in !3972. He tested this change with me together.