86-add-identity-classes

Conflicts:
	bwreg-jpa/src/main/java/edu/kit/scc/webreg/dao/RegistryDao.java
	bwreg-jpa/src/main/java/edu/kit/scc/webreg/dao/UserDao.java
	bwreg-jpa/src/main/java/edu/kit/scc/webreg/entity/UserEntity.java
	bwreg-service/src/main/java/edu/kit/scc/webreg/service/reg/impl/RegisterUserServiceImpl.java