BOMs refactoring

Please DON'T MERGE THIS YET. It is still work in progress, but I want to get early feedback from others, so that's why I am creating this PR.

We discussed some of the changes with @ge0ffrey @rafabene and @pmuir in past few weeks. With @ge0ffrey  we decided _not_ to move the BOMs to community repositories as they should only be released when product is actually released. We will still create a CI job that will locally build the BOMs and quickstarts and will sure they work as expected.

The following changes should be done as part of the refactor:
* introducing `brms-bmpsuite-bom-parent` that will contain the shared info like version properties, etc
* added `jboss-brms-bpmsuite-bom` that contains only the drools/jbpm/optaplanner artifacts (no javaee stuff)
* refactored the `jboss-javaee-6.0-with-drools` into `jboss-javaee-6.0-with-brms-bpmsuite` as it already listed more than just Drools artifacts.


Unfortunately, this is the versions problem we have also been talking about. The community projects (that will be part of BRMS/BPM Suite 6.1.0) will be in version 6.2.0.x. The 6.2.0-SNAPSHOT version is in JBoss repo.

Currently this parent brings mainly the `version.org.kie` property. I am not sure if there is something else we could leverage from there?

We will definitely need to update this version when releasing the BOMs, so that is basically the same having the `version.org.kie` property there directly (and not using the kie-parent-metadata). @ge0ffrey WDYT?