remove old unused zookeeper dependent lookups code

[himanshug]

Paving Path Towards #9053

Description

This patch removes a bunch of lookups discovery code with hard coded use of Zookeeper. This code is no longer used at all and was originally kept to allow rolling upgrade transition to http based lookups management which is used currently by the coordinator for lookups management.

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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.
• 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.
• added integration tests.
• been tested in a test Druid cluster.

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[himanshug]

@clintropolis thanks for quick review.