Add option for sampling idle recently active sessions

[nenadnoveljic]

What does this PR do?

Adds an option to sample recently active idle sessions.

Motivation

Improve APM/DBM correlation by ~3x.

For example, the execution plan for the query below, which ran in 2ms, was captured only after several executions:

Details

Capturing queries is essential for APM/DBM correlation. Currently, only active sessions are sampled, missing many fast queries. By sampling idle sessions that were recently active, we can significantly increase the number of captured queries.

Trade off

The option is disabled by default because, in SQL Server, identifying queries from idle sessions requires a second scan, doubling activity collection time.

Dependencies

Sampled idle sessions are excluded from the active sessions graph but appear in the samples with the Wait Event set to Other. If we don't filter them, they should be marked as Idle.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add the qa/skip-qa label if the PR doesn't need to be tested during QA.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged

[codecov]

Codecov Report

Attention: Patch coverage is 93.93939% with 2 lines in your changes missing coverage. Please review.

Project coverage is 89.47%. Comparing base (35e3533) to head (36738f6).
Report is 15 commits behind head on master.

Additional details and impacted files

Flag	Coverage Δ
activemq	?
cassandra	?
hive	?
hivemq	?
hudi	?
ignite	?
jboss_wildfly	?
kafka	?
presto	?
solr	?
sqlserver	91.59% <93.93%> (+9.98%)	⬆️

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