Demo: Exploring non-key joins of Kafka Streams 2.4

KIP-213 introduced non-key joins on KTables in Kafka Streams. This allows for joins also on tables derived from topics that don't share the same message key. An example in the context of Debezium could be two tables, customer and address, with a FK relationship from address to customer. These two tables would have different primary keys and thus also change data topics would not have the same key. A demo should show how the two table streams (or rather KTables, I suppose) can be joined on the FK from address to customer. This should be based on the Quarkus extension for Kafka Streams.