Continue to refine M2-M3 upgrade pipeline

[wendellpiez]

User Story:

The SSP example at https://github.com/brianrufgsa/fedramp-automation/blob/sap-sar-poam/templates/ssp/xml/FedRAMP-SSP-OSCAL-Template.xml is showing that the upgrade pipeline (converting from Milestone 2 to Milestone 3 OSCAL) is defective in several respects.

Goals:

Complete this conversion while improving the upgrade tool (XSLT pipeline) to the extent practical.

Dependencies:

There are a couple of small tweaks that might be accomplished by hand in this conversion; but anything 'normal' should be handled by the pipeline.

Acceptance Criteria

• [x] XSLTs in the repository in src/release/content-upgrades are updated with improvements better supporting Milestone 2 to Milestone 3 conversion (especially SSPs), with appropriate regression testing.
• [x] The improved SSP template XML has been offered back to FedRAMP
• [x] All OSCAL website and readme documentation affected by the changes in this issue have been updated. Changes to the OSCAL website can be made in the docs/content directory of your branch.
• [x] A Pull Request (PR) is submitted that fully addresses the goals of this User Story. This issue is referenced in the PR.
• [x] The CI-CD build process runs without any reported errors on the PR. This can be confirmed by reviewing that all checks have passed in the PR.

{The items above are general acceptance criteria for all User Stories. Please describe anything else that must be completed for this issue to be considered resolved.}

[wendellpiez]

There are a couple of outstanding issues here to discuss with @david-waltermire-nist and @brianrufgsa, but this is mostly ready.

Specifically:

• correct mapping of service and leveraged-authorization
• possible (small) anomalies in FedRAMP SSP template

[wendellpiez]

There appear to be errors in the PR due to broken links in Markdown?

[wendellpiez]

Improvements having been merged this is probably closable.