Align versions across poms on each module

We recently aligned the pom's within each jboss tools module svn to have "natural parents" meaning the only pom within a module that refers the parent pom is the "root" one.
i.e. hibernatetools/pom.xml instead of all plugins and features inside the module.

That made updating parent pom's easy, now we should just get the pom versions aligned within the module to allow easy update of versions in that module without manual tweaking of files.

What this allows is that you can use commands like this:
mvn org.eclipse.tycho:tycho-versions-plugin:set-version -DnewVersion=3.4.0-SNAPSHOT

and tycho will take care of updating all pom/manifest/feature.xml/product defs for that module subdirectory.
(if the references are outside that directory then of course things won't be updated automatically)

The changes i'm planning will do two things:

1) Align all versions within one module (that is needed for the one command version update)
2) Remove all redundant <version> references when the parent reference is enough.

Please note, that if a module owner wish to manage individual plugin versions that is perfectly still doable
they just need to add the explicit <version> reference and cannot rely on the one command version update
to work automatically.