Improve query log diffs

What does this MR do?

This improves our tooling by providing more useful query log diffs as part of exceed_query_limit.

Rather than just listing out the unique queries in the example, this now prints out queries grouped by meaningful prefix, so that the developer can quickly scan them to see how they differ, and aggregated counts are listed, so that users can see whether queries are run in one side or the other.

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.