[GSS](6.4.z) Improve ExtensibleXmlParser logging

If BPMN process includes some error it's hard to track it down due to ambiguous logging.

I am attaching one process definitions which demonstrates this. During the build of the attached process following error is produced:

14:15:22,735 ERROR [org.drools.core.xml.ExtensibleXmlParser] (http-127.0.0.1:8080-2) (null: 4,281, 181): cvc-complex-type.2.4.a: Invalid content was found starting with element 'bpmn2:endEvent'. One of '{"http://www.omg.org/spec/BPMN/20100524/MODEL":artifact, "http://www.omg.org/spec/BPMN/20100524/MODEL":resourceRole, "http://www.omg.org/spec/BPMN/20100524/MODEL":correlationSubscription, "http://www.omg.org/spec/BPMN/20100524/MODEL":supports}' is expected.

There are three suggestions:

1) Include the process filename in the message
2) Include the node id in the message - so when inspecting the actual *.bpmn file we can find the specific node
3) Seems like this error is not really an error - but just a minor inconsistency, because the build succeed and the process can be executed without any issues. If you agree, maybe ERROR level should be change to WARN/INFO/DEBUG..