GH-194: Make KafkaEmbedded as a bean

[artembilan]

Fixes: #194

To avoid concurrent calls of the shutdown hooks make an KafkaEmbedded
as a Lifecycle to let ApplicationContext to call stop() before
destroying itself

That way the Kafka servers and zookeeper and also working directory
are destroyed and removed before JMV shutdown hooks
and FileNotFoundException /tmp/kafka-3266968904825284552/replication-offset-checkpoint.tmp
should disappear

[garyrussell]

Cool!

We should add some docs above here. Something like...

It is generally recommended to use the rule as a @ClassRule to avoid starting/stopping the broker between tests (and use a different topic for each test). If you are using Spring's test application context caching, you can also declare a KafkaEmbedded bean, so a single broker can be used across multiple test classes.

(plus some example configuration).

[artembilan]

Yeah,,, I also thought about something like @EmbeddedKafka on the test class level, but since I'm not familiar with the Spring Test Framework caching magic, I'm not sure that registering bean from that level would work as expected...

Just need to get some feedback from @hoaz to go ahead!

[artembilan]

Let's don't cherry-pick!
No issue from our side.
This feature can just be available from the 2.0 version

[garyrussell]

Merged as 6b5c087