Boot models

Reworking of how Hibernate processes "managed resources" (classes,XML) and builds its org.hibernate.mapping metamodel.

See hibernate/hibernate-orm#5998

The goals:

• Move away from reflection - this allows better support for runtime enhancement

• Facilitate the ability to move away from HCANN (to Jandex)

• More uniform handling of XML

• Use of better defined stages to reduce the need for so many SecondPass registrations