Exclude zookeeper dependency from the project

[danielezonca]

Zookeeper is a transitive dependency in ModelMesh (see litelinks-core and kv-utils) but it is not used when ModelMesh is used in K8s via modelmesh-serving controller so it should be possible to remove it.
The main benefit of this is to reduce the dependency tree thus the surface attack of the project when used in K8s.

The usage of ModelMesh "core" as standalone component with Zookeeper is not really a documented/supported use case but it should remain possible adding Zookeeper back manually.

[njhill]

For now we can update zookeeper to avoid the CVE: #128