fix: ensure query timeout is respected at router

[jtuglu1]

Description

We have seen queries fail to reach upstream brokers for a variety of reasons (lack of available broker connections, DNS issues, etc.). In these cases, the router does not fall-back to a sensible timeout (defaulting to the 15mins connection timeout). Since the router is part of Druid, we should be treating the maximum timeout as the min(query timeout, configured router<-->broker connection timeout) to avoid pathological cases where users expect a result in ≤ {query timeout} but end up receiving it 15mins later (or whatever druid.router.http.readTimeout is set to).

Other databases separate timeouts into connection vs read timeouts, the former being a timeout on the time taken for the client to establish a connection to the server whereas the latter is a bound on the time taken to perform the actual query. This ensures Druid properly sets read timeout to be the minimum of druid.router.http.readTimeout and user-specified/cluster-configured default query timeout.

Release note

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Key changed/added classes in this PR

• MyFoo
• OurBar
• TheirBaz

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This PR has:

• been self-reviewed.
  • using the concurrency checklist (Remove this item if the PR doesn't have any relation to concurrency.)
• added documentation for new or modified features or behaviors.
• a release note entry in the PR description.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.