Add outdated fields to internal security reports comparison API

What does this MR do?

This MR adds fields to the internal security reports comparison API response so that it can be determined whether or not the base report used for comparison is "out of date".

This resolves the backend part of issue #4913 (closed).

Details

• Parsers have access to the JobArtifact, not just the JSON blob

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers