OpenStack UPI: introduce common playbook

[mandre]

The common playbook reads the infraID from metadata.json and computes
the resource names needed by other playbooks.

[pierreprinetti]

/retest

[pierreprinetti]

/approve
/label platform/openstack

[openshift-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: pierreprinetti

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[openshift-ci-robot]

@mandre: The following test failed, say /retest to rerun them all:

Test name	Commit	Details	Rerun command
ci/prow/e2e-libvirt	313c468	link	/test e2e-libvirt

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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[pierreprinetti]

/lgtm