(do not merge) OSDOCS-10863: PinnedImageSet draft doc

[skopacz1]

This PR is not intended to be merged. It is meant to host a draft of a doc for OSDOCS-10863, for the sake of reviewing, before the draft is converted into a KCS article.

The PR will be closed once the draft is reviewed and moved to a KCS.

[openshift-ci-robot]

@skopacz1: This pull request references OSDOCS-10863 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the story to target the "4.17.0" version, but no target version was set.

In response to [this](https://github.com/openshift/machine-config-operator/pull/4410): >This PR is not intended to be merged. It is meant to host a draft of a doc for [OSDOCS-10863](https://issues.redhat.com/browse/OSDOCS-10863), for the sake of reviewing, before the draft is converted into a KCS article. > >The PR will be closed once the draft is reviewed and moved to a KCS. Instructions for interacting with me using PR comments are available [here](https://prow.ci.openshift.org/command-help?repo=openshift%2Fmachine-config-operator). If you have questions or suggestions related to my behavior, please file an issue against the [openshift-eng/jira-lifecycle-plugin](https://github.com/openshift-eng/jira-lifecycle-plugin/issues/new) repository.

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: skopacz1 Once this PR has been reviewed and has the lgtm label, please assign cheesesashimi for approval. For more information see the Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files: - **[OWNERS](https://github.com/openshift/machine-config-operator/blob/master/OWNERS)** Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[openshift-ci[bot]]

@skopacz1: 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/e2e-vsphere-ovn-zones	bb5799f6c0f37f7454bb67f07240a136b7ec136d	link	false	/test e2e-vsphere-ovn-zones
ci/prow/e2e-vsphere-ovn-upi-zones	bb5799f6c0f37f7454bb67f07240a136b7ec136d	link	false	/test e2e-vsphere-ovn-upi-zones

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).

[openshift-bot]

Issues go stale after 90d of inactivity.

Mark the issue as fresh by commenting /remove-lifecycle stale. Stale issues rot after an additional 30d of inactivity and eventually close. Exclude this issue from closing by commenting /lifecycle frozen.

If this issue is safe to close now please do so with /close.

/lifecycle stale