Update Oracle Driver in ArjunaCore.arjuna

Currently, some Maven profiles in ArjunaCore.arjuna are expected to be executed after the qa module. As a consequence, when tests are run activating those maven profiles, builds fail. To fix this problem, qa and ArjunaCore.arjuna should be uncoupled. To do so, ArjunaCore.arjuna should download db drivers using the same mechanism used in qa and remove the dependency in the ArjunaCore.arjuna pom.xml file, specified with the <SystemPath> tag