Incorporate DBCP connection pooling into OptaPlanner persistence tests

Full downstream build revealed that OptaPlanner persistence tests depend on kie-test-util and thus are influenced by changes around Narayana + DBCP connection pooling. Current test fail due to Hibernate trying to call:
java.lang.UnsupportedOperationException: null
at org.apache.tomcat.dbcp.dbcp2.PoolingDataSource.getConnection(PoolingDataSource.java:162)
This method takes username and password, which is not supported by DBCP, as creating new connections should be delegated to underlying XA datasource. However, Hibernate calls this method when username and password are configured directly in persistence.xml.