Add rev 5 ruleset to web documentation

[danielnaab]

Extended Description
As a validations user, I would like the NIST RMF rev 5 ruleset to be browsable in the web documentation.

Preconditions

• The rev 5 ruleset exists, as supported by Support multiple versions of the validations #353

Acceptance Criteria

• Both rev 4 and rev 5 rulesets are browsable in the web documentation

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

[aj-stein-gsa]

We are not going to move forward with the current web UI approach, so I will close out this issue for now. For those who reported this issue or are following it, follow ADR 7 for more details.