Remove obsolete has-separation-of-duties-matrix

[aj-stein-gsa]

Constraint Task

• Remove the constraint
• Remove the test fixture files and YAML pass/fail test configurations
• Update website documentation on GSA/automate.fedramp.gov

Intended Outcome

We will remove the obsolete has-separation-of-duties-matrix as we make room for #809 and not confuse community evaluating the rules out of develop

Syntax Type

This is required core OSCAL syntax.

Allowed Values

There are no relevant allowed values.

Metapath(s) to Content

<!-- not applicable -->

Purpose of the OSCAL Content

No response

Dependencies

No response

Acceptance Criteria

• All OSCAL adoption content affected by the change in this issue have been updated in accordance with the Documentation Standards.
  • Explanation is present and accurate
  • sample content is present and accurate
  • Metapath is present, accurate, and does not throw a syntax exception using oscal-cli metaschema metapath eval -e "expression".
• All constraints associated with the review task have been removed
• A Pull Request (PR) is submitted that fully addresses the goals section of the User Story in the issue.
• This issue is referenced in the PR.

Other information

This removal will make way for alternative approach upcoming in #809.

(/cc @Telos-sa for awareness as it came up recently during an office hours, you may disregard that constraint violation fro the time being.)