add support for druid 0.22.1 and zookeeper 3.7.0

Fixes #256.

Upgrade Apache Druid in example specs for deploying a tiny druid cluster to version 0.22.1, to solve the critical vulnerability CVE-2021-44228 in Apache Log4j.
Upgrade ZooKeeper to 3.7.0, since starting with Apache Druid 0.22.0, support for ZooKeeper 3.4.x has been removed.
Fix breaking changes in ZooKeeper configuration parameters: clientPort and clientPortAddress. Starting with 3.5.0, this information is part of the server keyword specification.

This PR has:

[x] been tested on a real K8S cluster to ensure creation of a brand new Druid cluster works.
[x] been tested for backward compatibility on a real K*S cluster by applying the changes introduced here on an existing Druid cluster. If there are any backward incompatible changes then they have been noted in the PR description.
[ ] added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
[ ] added documentation for new or modified features or behaviors.

druid-io / druid-operator