Hello,
the problem message is:
Caused by: org.jboss.msc.service.DuplicateServiceException: Service jboss.persistenceunit."WebApplication2.war#org.jbpm.persistence.jpa" is already registered
You already have one application deployed, which uses persistence unit org.jbpm.persistence.jpa. Try to run your application in container alone and make sure that you have there only one persistence.xml with one such persistence unit.