INT-3579: AMQP Stop the Template if a Lifecycle

JIRA: https://jira.spring.io/browse/INT-3579

Implement `Lifecycle` in the AMQP outbound adapter and propagate
a `stop()` to the `AmqpTemplate` if it implements `Lifecycle`.
Even if `BatchingRabbitTemplate` is always `true` now, there is no guaranty in the future that it won't be changed or other `AmqpTemplate` will provide another implementation.