[WIP] Pass through of config variables to ironic

[derekhiggins]

Mark as a WIP as further discussion is needed, to be used with openshift/installer#3887

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Test name	Commit	Details	Rerun command
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ci/prow/unit	063d305	link	/test unit
ci/prow/e2e-azure	063d305	link	/test e2e-azure
ci/prow/e2e-azure-operator	063d305	link	/test e2e-azure-operator

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[derekhiggins]

OK will close this, looks like we'd rather add things when needed.