refactor two phase persistence unit services (PhaseOnePersistenceUnitServiceImpl + PersistenceUnitServiceImpl) into one service

Related feedback from https://github.com/wildfly/wildfly/pull/4722:

This is asymetrical, so if this service , and phase one are stopped, and then phase 1 is started again, phase 2 will appear started. The side effects seem minor though

We have a long term goal to somehow verify every service can be stopped and started with the expected effect. Right now many of our services are not restartable which makes potential new features like partial deployment standby hard to achieve. So Im just offering pointers whenever I see lifecycle symmetry issues.