Refactor Schematron for use with SchXslt (source: 18F/fedramp-automation: 545)

[danielnaab]

Original issue: 18F#545

Extended Description

• This is required if SchXslt (see Bump axios, saxon-js and xslt3 in /src/examples/javascript #529) is to be used.

Acceptance Criteria

• All Schematron assertion messages are declarative statements which affirm the positive test outcome.
• All Schematron assertion diagnostic messages are declarative statements which explain the negative test outcome.
• The Schematron code has no assertion failures when validated using src/validations/styleguides/sch.sch using the basic phase.
• XSpec unit tests for positive and negative Schematron assertion outcomes accompany all Schematron assertions (where feasible).

Story Tasks

• Refactor existing Schematron code so that all Schematron variables are unique within the schema.

Definition of Done

• Acceptance criteria met
• Unit test coverage of our code > 95%
• Automated code quality checks passed
• Security reviewed and reported
• Reviewed against plain language guidelines
• Code must be self-documenting
• No local tech debt
• Load/performance tests passed – needs to be created/automated
• Documentation updated
• Architectural Decision Record completed as necessary for significant design choices
• PR reviewed & approved
• Source code merged

[aj-stein-gsa]

Re ADR 7, we will not use the previous constraint architecture as-is and the relevant code will soon be removed. I am closing this issue as not planned.