feat: Promote kube_statefulset_ordinals_start from ALPHA -> BETA

[pwschuurman]

What this PR does / why we need it:
Promote kube_statefulset_ordinals_start metrics from ALPHA -> BETA

• KEP: Allow StatefulSet to control start replica ordinal numbering enhancements#3335

How does this change affect the cardinality of KSM: (increases, decreases or does not change cardinality)
Does not change the cardinality of KSM

[k8s-ci-robot]

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[mrueg]

I don't have any strong opinions here, I believe we haven't used beta before and went directly to stable.
Any thoughts on this from people that care more about metrics stability? @dgrisonnet @rexagod @CatherineF-dev @logicalhan

[dgrisonnet]

/triage accepted

I think this should wait for the next major since the current stability model only used Experimental and Stable.