Better granularity for imported BOMs

Projects/modules like Drools or OptaPlanner transitively require BOMs which are not actually needed at all (e.g. uberfire-bom or guvnor-bom). This brings a lot of issues for RPMs and is also weird.

We also need to make sure we an easily override dependencies coming from ip-bom. The only sensible way seem to directly inherit from ip-bom (instead of importing it). That of course results in a need to have a different parent for user BOMs, as we don't want to pollute them with all the 3rd party deps.

Proposal to fix this (discussed with gdesmet@redhat.com as the best option):

kie-parent (created from kie-parent-metadata)

• has ip-bom as it’s parent
• inherits the whole depMgmt from ip-bom. Contains all required dependency overrides.

• kie-user-bom-parent (new POM)
• has ip-parent as parent
• contains no depMgmt
• needs to copy some metadata from kie-parent (URL, SCM info, links, etc)

user-boms (kie-bom, drools-bom, optaplanner-bom, etc)

• have kie-user-bom-parent as their parent
• contain only depMgmt for the specific groupIds (e.g. org.optaplanner for optaplanner-bom)
• from user's POV nothing changes here

kie-platform-bom

• has kie-parent as it's parent
• import all the other BOMs (uberfire-bom, errai-internal-bom, etc)
• this BOM is useful in downstream projects, like tests

Specific projects then import only what they need (obviously not 100 % true as the kie-third-party-bom would define many more versions than we need, but that is not easily fixable atm):

Drools parent POM (top-level pom in drools repo)

• has kie-parent as it’s parent
• imports drools-bom (kie-bom is imported transitively)

jBPM Console NG parent POM

• has kie-parent as it’s parent
• drools-bom? + jbpm-bom + uf-bom + errai-bom+ dashuilder-bom + guvnor-bom