Various dependency clean-ups

Attempts to make the POM files a more accurate representation of what each module is actually using, and to standardise on placing versions in the root POM *only* (in the `dependencyManagement` section)

Testing: full unit test run; started Brooklyn and deployed MySQL+Tomcat cluster to localhost
Similar to previous similar comment. There were conflicting versions of jersey-server used in different parts of Brooklyn. I have settled on the latest versions of those being used and unified the dependencies. In this case it's affected this project. Again the comment was intended to be a pointer for me to test that the minor version change did not have bad side effects, so I will remove this comment before rebasing.