DSL: Fixes and polishing after upgrade

* Upgrade to SI 4.0.3 and Boot 1.1.4
* Add `HeaderEnricherSpec#headerChannelsToString()`
* Fix `DslRecipientListRouter` according core changes
* Fix `Amqp` and `Jms` modules for the bug around "All Message creators need a BeanFactory"
using fake `new DefaultListableBeanFactory()` for `(Amqp)JmsChannelFactoryBean`