Improve eap compatibility test execution

This is a followup of JBIDE-23756 - with that, we are once again able to execute compatibility tests for eap. But there are a few things missing:

For now I will make it work with what we have, but there are several things that need to be fixed:
1. Even if you only run the eap7x-compatibility profile, all of the runtimes (jboss as 4, as 5, as 7, wildfly...) will be downloaded anyway, because this is set up in as/itests/pom.xml - we need to come up with a way to only do this if the compatibility profile is not active. Maybe we need to switch to profile activation by property, e.g. eap7x-compatibility - the profile in as/itests/org.jboss.tools.as.ui.bot.itests/pom.xml would be activated by this, whereas all the other runtime downloads in as/itests/pom.xml would be in a profile that is deactivated using this property.
2. https://github.com/jbosstools/jbosstools-server/blob/master/as/itests/org.jboss.tools.as.ui.bot.itests/pom.xml#L48
The eap7x-compatibility profile has jboss-eap-7.0 server directory hardcoded. You can still override the whole property with something else for eap 7.1, but it would be nice to improve this.

For reference, this is a job where Radim demonstrated the new way to execute tests:
https://dev-platform-jenkins.rhev-ci-vms.eng.rdu2.redhat.com/view/All/job/eapCompatibility_rhopp_temp/

And these are the two jobs EAP QE uses for the compatibilty testing:
https://eap-qe-jenkins.rhev-ci-vms.eng.rdu2.redhat.com/job/eap-70x-jbds-compatibility-jbosstools-4.4.x-RHEL/
https://eap-qe-jenkins.rhev-ci-vms.eng.rdu2.redhat.com/view/EAP7/view/EAP7-JBDS/job/eap-7x-jbds-compatibility-jbosstools-4.4.x-RHEL/