Revert "anticipating FindBugs warnings : fixed field visibility + using immutable state contructor parameter"

This reverts commit 0b11accbf5878a4c43119e650b1375e3bb3837b5.
TestDocumentBean should have accessor methods in order to be handled properly by Jackson and make findbugs happy at the same time + unmarking @Ignore but renamed the class to BulkIT so it is not run by surefire
introduced failsafe maven plugin in order to execute integration tests with mvn verify -DskipITs=true
manual merge of FixBugInBulkTest to integration