feat(validate): save validation resources

[meganwolf0]

Description

Adds a flag save-resources to validate to save the resources to the backmatter of an assessment result

Related Issue

Relates to #301

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Test, docs, adr added or updated as needed
• Schema Updates applied
• Contributor Guide Steps followed

[brandtkeller]

Documenting for posterity:

Moving forward with consideration of the use of back matter more carefully. If we can meet our outcomes with a separate external file as-is today - we should execute on that strategy now while evaluating whether we continue to repeat the back matter storage pattern.

[meganwolf0]

Removed back-matter option and associated code changes needed, definitely simplifies things!

[brandtkeller]

Few items to cleanup. Also understand this was a discovery and exploration driven PR as opposed to a direct issue deliverable - so I have no issues with undocumented requirements/additions (in the issue).