This commit streamlines the Integration Starter by removing the file
http, ip, and stream modules as they are not always used by a majority
of apps that use Spring Integration and can also pull in other, unwanted
dependencies.

Additionally, a dependency on spring-integration-java-dsl has been
added. This makes it easy for users to configure Spring Integration
using Java configuration (the recommended approach), rather than via
XML. The Integration sample has been updated to use the DSL. Further
improvements could be made once the sample is using Java 8.

Closes gh-5528