Make sketch encoding configurable

[adarshsanjeev]

Makes sketch encoding in MSQ configurable by the user. This would allow a user to configure the sketch encoding method for a specific query.

The default is octet stream encoding.

Release notes

• Add a sketchEncoding query context parameter that controls the sketch encoding format between workers in MSQ. Allowed values are JSON or OCTET_STREAM. The default value is OCTET_STREAM.

---

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.