KAFKA-12281: Deprecate BrokerNotFoundException (apache#20192)

Implements KIP-1195.

BrokerNotFoundException exception is unused since 2.8  Marking it
deprecated so that it can be removed in next major release.

Reviewers: Matthias J. Sax <matthias@confluent.io>

Author: karuturi

streams/src/main/java/org/apache/kafka/streams/errors/BrokerNotFoundException.java

@@ -21,8 +21,10 @@
  * could be found.
  *
  * @see org.apache.kafka.streams.StreamsConfig
+ * @deprecated since 4.2 and should not be used any longer.
  */
 @SuppressWarnings("unused")
+@Deprecated
 public class BrokerNotFoundException extends StreamsException {
 
     private static final long serialVersionUID = 1L;