Investigate issues with SSL Auth that affect discovery-kubernetes-api when we use K8s v1.30+

K8s v1.30 seems to have something that stops our SSL Auth from working - causing SSL Handshake issues.
Seen in #455

If we run the tests with newer JDKs than the Java 8 ones used in our K8s Integration tests, the SSL Handshake issues go away. So it seems like Java 8 may not necessarily support the cipher suites that we need. The integration tests don't pass but they fail with other SSL issues associated with incomplete SSL setup (no client keystore, for one).

Start with the SSL Auth failure described in #455 and run the Kubernetes integration tests against K8s v1.30+ with Java 8 and a newer JDK. Compare the SSL handshake behavior and inspect the incomplete SSL setup, including the missing client keystore. Done means the Java 8 cipher-suite compatibility and remaining SSL setup issue are identified and the integration-test outcome is explained.

Written by the indexing model from the issue text.