Document use of JAR artifact to build Debezium scripting SMT into Kafka Connect

Follows up on DBZ-2581 Add script SMT test case to OCP test suite.

• When you use the Streams build mechanism to incorporate Debezium connectors together with the scripting SMT into a Kafka Connect instance, to ensure that connectors function properly, the Kafka Connect CR must download the script language files from Maven as JAR artifact types. 
• Do not use Maven artifacts to fetch the scripting language dependencies. If you reference the scripting libraries as Maven artifacts, when Maven retrieves the artifacts, it also fetches transitive dependencies, which can create conflicts in the environment's class path by introducing incompatible libraries.