nokubeconfig controller: use listers, filter informer events, avoid applies

[vrutkovs]

In order to make controller sync less often this commit reworks it:

• remove unused informers
• filter events - run sync when either source or target configmaps change
• use listers instead of direct client gets
• avoid applies unless configmap contents change

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: vrutkovs

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[vrutkovs]

/test e2e-short-cert-rotation

[vrutkovs]

/test e2e-short-cert-rotation

[openshift-ci]

@vrutkovs: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/okd-scos-e2e-aws-ovn	d2115d0	link	false	/test okd-scos-e2e-aws-ovn
ci/prow/e2e-aws-ovn	d2115d0	link	true	/test e2e-aws-ovn
ci/prow/e2e-aws-operator-disruptive-single-node	d2115d0	link	false	/test e2e-aws-operator-disruptive-single-node
ci/prow/e2e-gcp-operator-single-node	d2115d0	link	false	/test e2e-gcp-operator-single-node

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