Display SSP Authorization Boundary

[rgauss]

As a user of the OSCAL Viewer, I want to see the Authorization Boundary of a System Security Plan (example) including any specified inline images so that I can understand the scope of the ATO.

Acceptance Criteria

• A Authorization Boundary section is displayed in System Characteristics if present in the OSCAL SSP
• The Authorization Boundarydescription field is displayed
• The Authorization Boundary remarks is displayed
• Any Authorization Boundary diagram images are displayed with any defined caption

Implementation Notes

• We're likely to develop a Diagram component that can be re-used across Authorization Boundary, Network Architecture, and Data Flow components
• We could potentially modify the existing oscal-rest-service test SSP to include an authorization boundary section pointing to an actual image, but any example SSP with that data will suffice

Subtasks

• Add OSCALDiagram component
• Add display of OSCALDiagram authz boundary to SSP
• Add authz boundary segment and diagram to test data in REST service
• Added support for resource content GET requests oscal-rest-service#49