[DO NOT MERGE]: validates assumptions about duplicate extensions and kargs

[cheesesashimi]

This PR does two primary things which are intended to be more illustrative as opposed to something that we should merge directly:

1. It adds additional test cases to ctrlcommon.MergeMachineConfigs() in order to validate the assumption that we do not de-duplicate kernel arguments or extensions and that we preserve the order of the individual kernel arguments and extensions lists.
2. It adds some additional helpers to aid in determining string slice equality, element uniqueness, etc. as well as tests to validate their correctness.

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cheesesashimi

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[openshift-merge-robot]

PR needs rebase.

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