Create example for using RIG to forward database change streams to clients

[Knappek]

The awesome project Debezium is an open source project for change data capture that streams changes from your database. By pointing Debezium on a database, you can respond to all of the inserts, updates and deletes of a database. Debezium's basic architecture is to listen to database events and forwarding them to Kafka. See more details on their architecture documentation. Debezium can be integrated with a number of 3rd party projects but does not forward these events to client side applications.

This is where RIG kicks in. We could create a new example in our examples directory where we subscribe to the Kafka topic, to which Debezium produces the database change events, and forward them to clients. With this architecture, mobile apps or SPAs can "directly" subscribe to database events and reload the data in the frontend immediately without reloading the page. You can then achieve a similar experience as in Firebase.