[WIP] Explanatory Documentation and Notes for OSCAL Rules and Test Enhancements

[aj-stein-nist]

Committer Notes

This document is draft notes that will later be adapted into one or more pages in the pages.nist.gov/OSCAL to ready ongoing work from NIST and community contributors on educational framing content for #1058.

All Submissions:

• Have you selected the correct base branch per Contributing guidance?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Have you squashed any non-relevant commits and commit messages? [instructions]
• Do all automated CI/CD checks pass?

Changes to Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your core changes, as applicable?
• Have you included examples of how to use your new feature(s)?
• Have you updated all OSCAL website and readme documentation affected by the changes you made? Changes to the OSCAL website can be made in the docs/content directory of your branch.

[aj-stein-nist]

TODO: Dave requested in a sync today I collapse this PR into a feature branch, not develop.