OSCAL profile resolution pipelines

[wendellpiez]

Committer Notes

A first effort at supporting OSCAL profile resolution in a portable runtime.

Using the same infrastructure as everything else:

• Produce OSCAL catalogs as specified by profiles
  • Examples provided or bring your own
• Use the official XSLT resolver in the OSCAL repo
• Or bring a copy of the XSLT (pipeline) onto the local system
  • Offline use
  • Debugging and analysis

All Submissions:

• Follow Contributing guidelines
• Make no changes duplicating or conflicting with other open Pull Requests
• Have been squashed to keep only relevant interim commits, if any [instructions]
• Have been tested manually
• Pass all CI/CD checks

Changes to Core Features:

• The Issue history, discussions and new documentation provide context for new features -- everything is reasonably self-explanatory
• New tests are included
• New examples are included
• Everything in readme and TESTING documents has been updated

[galtm]

I might have more comments later, but I wanted to publish the ones I have so far. If you're inclined to merge this PR and consider incremental improvements later, no problem!