OSDOCS On Cluster Layering: Install Time Support

[mburke5678]

https://issues.redhat.com/browse/OSDOCS-17685

This PR creates a module to document how to create the required MOSC and push secret objects. I added an ifeval for the verification steps, in case we want the module in the image mode docs and the install docs. I assume the verification steps won't work in the install docs, at least not in that module.

Need to work with the install folks to determine the best way to present this information.

Link to docs preview:

QE review:

• [ ] QE has approved this change.

[ocpdocs-previewbot]

🤖 Wed Dec 17 18:28:48 - Prow CI generated the docs preview:

https://104088--ocpdocs-pr.netlify.app/ https://104088--ocpdocs-pr.netlify.app/openshift-enterprise/latest/machine_configuration/mco-coreos-layering.html

[openshift-ci[bot]]

@mburke5678: all tests passed!

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