Add Hibernate calls to DatabaseManager
Add Hibernate calls to DatabaseManager

As per Hibernate convention, a Data Access Object (DAO) serves as layer
of abstraction between the actual application and the database it works
off of. Since this was DatabaseManager's original purpose, it naturally
follows that Hibernate calls are added here.

main changes:
- create Session and SessionFactory
- use Hibernate to persist id in addIdList method

missing changes:
- missing javadocs

Khyzad/PID-webservice,HawaiiStateDigitalArchives/PID-webservice,HawaiiStateDigitalArchives/PID-webservice,Khyzad/PID-webservice