Java: Enable creation and termination of Valkey clusters during test

[jamesx-improving]

In all other bindings, we have the capability of creating a Valkey cluster with customized configuration, as well as stopping it, during a test, except for Java, with which we can only create or stop cluster as a gradle task.

This issue is aiming to provide a utility function for all Java tests to be able to create and terminate a cluster in the middle of the test, with a method invoke.