Revert "Added configurable ProducerRecord to ConsumerRecord mapper. T…

…he default mapper does not include metadata and headers. Alternative mappers can now be specified."

Reapplied without previous reformatting.

This reverts commit 0589e41.

assurance/src/main/java/com/obsidiandynamics/jackdaw/MockKafka.java

@@ -116,7 +116,7 @@ public Future<RecordMetadata> send(ProducerRecord<K, V> r, Callback callback) {
             } else {
               final Future<RecordMetadata> f = super.send(r, (metadata, exception) -> {
                 if (callback != null) callback.onCompletion(metadata, exception);
-                ConsumerRecord<K, V> consumerRecord = recordMapper.apply(r, metadata);
+                final ConsumerRecord<K, V> consumerRecord = recordMapper.apply(r, metadata);
                 enqueue(consumerRecord);
               });
               return f;