Add topic routing by field option for New Record State Extraction

Currently the New Record State Extraction doesn't support the option of routing based on a certain field from the table. For my current use case I'd need to set a topic based on a varchar field in the table.

My first attempt was combining ExtractTopic SMT (https://docs.confluent.io/current/connect/transforms/extracttopic.html) with Debezium. This works nicely, except for delete as the `after` struct is null and the SMT fails because it can't set the topic. In case of delete, you'll need to use the field value from the `before` struct while in create / update the `after` struct should be used.

So my next option was expending the SMT. Based on the existing code for the Outbox Event Router SMT I've added a few lines of code to the SMT which take care of routing for CREATE, UPDATE and DELETE events.