Allow running e2e tests for azure

[alvaroaleman]

This change makes the platform used during e2e tests configurable
(defaulting to AWS for compatibility) and adds additional flags so they
can be executed against Azure.

Ref https://issues.redhat.com/browse/HOSTEDCP-243

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, use fixes #<issue_number>(, fixes #<issue_number>, ...) format, where issue_number might be a GitHub issue, or a Jira story:
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Checklist

• Subject and description added to both, commit and PR.
• Relevant issues have been referenced.
• This change includes docs.
• This change includes unit tests.

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alvaroaleman

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[openshift-ci]

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[enxebre]

/lgtm