In order to join the Spring Cloud release train we have to align the
dependencies and (more importantly) the dependency management strategy.
The strategy is to not put version ids in <dependencies> (only
in <dependencyManagement>) where possible. And more importantly
we cannot use the releae train itself (creates a cycle).
This change achieves most of that (and mkae it possible for client
apps to use spring-cloud-starter-parent:Brixton.BUILD-SNAPSHOT)
Add spring-integration bom
