Start using helpers from k8s.io/component-helpers

[damemi]

With the new k8s.io/component-helpers repo, we can start replacing many of the helpers that were duplicated in 431597d with their new external equivalents.

This function will depend on the PR kubernetes/kubernetes#95531 to make it available in the new repo

[damemi]

/hold
for upstream PR

[damemi]

/hold cancel
/cc @seanmalloy @ingvagabund
This sets us up to start importing more helpers and remove dupe code 🎉

[ingvagabund]

1. Are there any stability guarantees of the imported helper function? Stronly enforced during PR reviews
2. Any blockers for importing k8s.io/component-helpers in the descheduler repository? The repository is a staging repository, thus pulling only other staging repositories, not bringing anything from outside. The first release is aligned with 1.20 at which point descheduler will no longer rely on a non-release revision. In order to provide k8s stability guarantees of the descheduler itself, all k8s dependency versions need to align with the same k8s release. The next descheduler release is planned for 1.20 at which point all k8s dependencies (including k8s.io/component-helpers) will get pinned to 1.20.
3. How using of k8s.io/component-helpers repo is going to affect this repository? Removing and avoiding duplicates

In future, the descheduler will depend more on k8s.io/component-helpers once the scheduling framework is fully migrated under k8s.io/kube-scheduler. This is a necessary prerequisite to achieving that goal.

[ingvagabund]

Until there's the first release of k8s.io/component-helpers, there are no stability guarantees of the API in the right sense even though the stability intention is strongly enforced in k8s.io/component-helpers PR reviews. Given the descheduler is the first repo outside of kubernetes org to import the new staging repo and for the stability assumption mentioned above, we can use the descheduler repo as a guinea pig until the first release is out.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: damemi, ingvagabund

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[ingvagabund]

/lgtm