CNDB-17661: Add documentation for slow query logger (#2475)

[djatnieks]

Adds a new SlowQueryLogger.md document describing how to operate the
slow query logger, descriptions of the included metrics,
and some guidance on how to analyze metrics.

Also adds missing JavaDoc for the metrics in IndexContext,
which end up printed in the slow query log reports.

There is a very small reordering of some IndexContext metrics are
related reports to try to keep related things together.

[github-actions]

Checklist before you submit for review

• This PR adheres to the Definition of Done
• Make sure there is a PR and ticket in the CNDB project updating the Converged Cassandra version
• Use NoSpamLogger for log lines that may appear frequently in the logs
• Verify test results on Butler
• Test coverage for new/modified code is > 80%
• Proper code formatting
• Proper title for each commit staring with the project-issue number, like CNDB-1234
• Each commit has a meaningful description
• Each commit is not very long and contains related changes
• Renames, moves and reformatting are in distinct commits
• All new files should contain the IBM copyright header instead of the Apache License one (no DataStax copyright any longer)

[djatnieks]

Fixed minor conflicts in QueryContext

Added commit to remove unused setFilterSortOrder method from QueryContext

[plpesvc-ds]

❌ Build ds-cassandra-pr-gate/PR-2484 rejected by Butler

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4 regressions found
See build details here

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Found 4 new test failures

Test	Explanation	Runs	Upstream
o.a.c.db.compaction.CompactionsCQLTest.testCompactionInvalidPartitionDeletion (compression)	REGRESSION	🔴🔵	0 / 30
o.a.c.distributed.test.CasCriticalSectionTest.criticalSectionTest	REGRESSION	🔵🔴	0 / 30
o.a.c.index.sai.cql.VectorCompaction100dTest.testOneToManyCompaction[version=ec enableNVQ=true] ()	NEW	🔴⚪	0 / 30
o.a.c.index.sai.cql.VectorSiftSmallTest.testSiftSmall[ed false] ()	NEW	🔴⚪	0 / 30

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Found 4 known test failures