Change vagrant box source of centos9 to generic cloud image

[chandramerla]

What this PR does / why we need it:
Currently centos9, which is the base disk image used for creating nodes in k8s providers, is vagrant box type. So to be usable with qemu-system, this is converted to qcow2 and later used. As generic cloud image (in qcow2 format) already exists in centos9 mirror, where we download centos9 images from, we can directly use that, as we are doing that in PR where we are adding s390x support in providers. This requires removing the conversion from box to qcow2 format and replacing vagrant user with cloud-user whereever required.
Note: This PR is just a placeholder for now, so the draft PR

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• d1357ef Added TODO placeholder to change vagrant box source of centos9 to generic cloud image

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