INTEXT-121 Add Lifecycle to Outbound Adapter

JIRA: https://jira.spring.io/browse/INTEXT-121

When using `async` producers, the buffered messages need to be flushed.

Previously, when the context was stopped, such messages were lost.

- Implement `Lifecyle` in the outbound adapter and propagate the `stop()` to the underlying producer(s).
- Remove unused attributes from the consumer parser.
- Add a test case to show the buffered message is received after closing the producer.
- Add KafkaRunning JUnit `@Rule`
???
So, If I'm going to extend this class and implement `doStart()`, but `LOGGER.isDebugEnabled() == false`, my custom `doStart()` never be invoked.
I guees the better solution is in that `if...else` for `stop()`.

Right now it's only single concern to your PR. 
Let me know and I polish and merge it to go ahead with conflicts to my PR.