Add access to JMX metrics to Kafka Connect in DebeziumContainer

In order to have integration-tests that run connectors in Kafka Connect in the DebeziumContainer with snapshotting we need to be able to wait for snapshotting to be completed. This is not possible with the Kafka Connect API. In the normal tests we have direct access to JMX metrics and we check the status directly.

For DebeziumContainer we need to access the JMX exporter that comes in the Debezium container images and provide hlelper methods inside DebeziumContainer to check and wait for connectors to finish streaming.