Allow for the PDB to be more configurable

[peterabarr]

What would you like to be added:

I would like the PDB to be user modifiable so that it can accept new fields such as unhealthyPodEvictionPolicy.

Why is this needed:

To be able to make use out of new features in Kubernetes within metrics server.

/kind feature

[dgrisonnet]

cc @stevehipwell

/triage accepted
/help

[k8s-ci-robot]

@dgrisonnet:
This request has been marked as needing help from a contributor.

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In response to this:

cc @stevehipwell

/triage accepted
/help

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