[WIP] Add CentOS7 logic to registration scripts for testing purposes

[plorinc]

Description

Please describe your change and provide as much context as possible.

Fixes # (issue)

Change Type

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• Bug Fix (a non-breaking change which fixes an issue)
• New Feature (a non-breaking change which adds new functionality)
• Documentation Update (a change which only updates documentation)

Checklist

Please check off each item if the requirement is met.

• I have verified that my code follows RMT's coding standards with rubocop.
• I have reviewed my own code and believe that it's ready for an external review.
• I have provided comments for any hard-to-understand code.
• I have documented the MANUAL.md file with any changes to the user experience.
• RMT's test coverage remains at 100%.
• If my changes are non-trivial, I have added a changelog entry to notify users at package/obs/rmt-server.changes.

Other Notes

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