Added dependencies POM for Atomikos JTA library.
Added atomikos to module list.
Added XADataSourceFactoryBean so that we can construct XADataSource
instances based on the config from opennms-datasources.xml.
Added XADataSource support to the TemporaryDatabase interface so that we can
use TemporaryDatabase instances as JTA data sources.
Added Atomikos dep to opennms-dao and updated applicationContext-dao.xml so that
it uses Atomikos JTA library to provide JTA data sources and transaction managers
for Spring and Hibernate.
Fixed some unit tests to work after JTA updates.