docs: Add cleanup section to the contributor ladder doc

[jonathan-innis]

Fixes #N/A

Description

Adds a section to the contributor ladder doc on the process for removing reviewers and moving approvers to emiritus

How was this change tested?

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jonathan-innis

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[coveralls]

Pull Request Test Coverage Report for Build 13727726084

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 6 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.05%) to 81.593%

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Files with Coverage Reduction	New Missed Lines	%
pkg/test/expectations/expectations.go	2	95.0%
pkg/controllers/disruption/consolidation.go	4	85.55%

Totals
Change from base Build 13727397084:	-0.05%
Covered Lines:	9597
Relevant Lines:	11762

---

💛 - Coveralls

[jmdeal]

/lgtm