Prepend prefix for MAR operations

[adityapatwardhan]

PR Summary

• Prepend the standardized psresource MAR prefix
• Block publish to MAR
• Recognize mcr.microsoft.com as ContainerRegistry repository
• Add tests

PR Context

PR Checklist

• PR has a meaningful title
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• Summarized changes
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
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• Breaking changes
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  • Documentation needed
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  • Documentation needed
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  • N/A or can only be tested interactively
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[anamnavi]

LGTM. Eventually maybe we add a test for find and install