Improve the 'retrieve-tests-metadata' and 'update-tests-metadata' jobs

What does this MR do?

Also, consolidate the Knapsack report into a single file, and consolidate the RSpec EE-specific job from the RSpec base job.

I've left inline notes to better explain the changes.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content