OSCAL template directory

[danielnaab]

Restructure the /content directories to be organized by NIST RMF revision.

AC

• /src/content -> src/content/rev4
• /src/content/baselines/rev4 -> /src/content/rev4/baselines
• same changes as above in /dist

NOTE: the OSCAL process content job might not delete old dist directories. Verify that dist is clean process content is committed to the git repository.

Definition of Done

• Acceptance criteria met
• Unit test coverage of our code > 90% - needs automation story
• Accessibility tests pass - needs automation story
• Automated code quality checks pass
• Security reviewed and reported - check in with Wes on what we could do here
• Reviewed against plain language guidelines
• Design QA passed
• Code must be self-documenting
• No local tech debt
• Documentation updated
• Architectural Decision Record completed as necessary for significant design choices
• PR reviewed & approved
• Source code merged