SMT for DDL changes

[subkanthi]

https://issues.apache.org/jira/browse/KAFKA-9673

https://cwiki.apache.org/confluence/display/KAFKA/KIP-585%3A+Filter+and+Conditional+SMTs

For example, with Debezium there are topics which represent a schema change and topics which represent a data change, and users might want to apply transformations selectively, based on the topic type. SMTs cannot currently do this, since they're applied to all records produced by a source connector, irrespective of their intended topic. This problem would be solved if it was possible to apply an SMT according to the name of the topic (See KAFKA-7052 for further details).