Is your feature request related to a problem? Please describe:
New cpu metrics added recently and QE will be able to test them only in the next version.
so we need to add ALPHA label to the metrics so users will know it's not tested fully yet.
During this we were exposed to the option to add a new field; stability level, to the metrics.

Describe the solution you'd like:
We would like to add this field to all kubevirt metrics and not just news in order to maintain uniformity and to allow similar situations in the future.

Describe alternatives you've considered:
We considered adding manually [ALPHA] near the metrics description.

Additional context:
References:
https://github.com/kubernetes/community/blob/master/contributors/devel/sig-instrumentation/metric-stability.md
https://github.com/kubernetes/enhancements/tree/master/keps/sig-instrumentation/1209-metrics-stability

GitHub issue: https://github.com/kubevirt/kubevirt/issues/9139

*Important Note: before closing this ticket we will need to revert https://github.com/kubevirt/kubevirt/pull/9518.