[IZPACK-1097] Analyze and clean up dependencies

Currently, on running 'mvn dependency:analyze' there is reported a couple of unused declared dependencies and also used undeclarted dependencies. This should be resolved to make the Maven build and order of module builds in the reactor clean.

Furthermore there are dependency conflicts on transitive dependencies. Different versions should be unified or pinned in the dependencyManagement section of the parent POM.

The org.easytesting:fest* conflicts should be already resolved.

Next time we will hopefully beat the rest of those conflicts.