Remove Hibernate 4.2 module for WildFly

Development note: This change requires the removal of the JDBC wrapper classes in org.zanata.database, which were intended to detect certain misuses of JDBC classes during tests, but in practice they haven't detected much, if anything, and aren't worth their maintenance costs (as currently implemented).

If we want to bring the JDBC wrappers back, instead of activating them with Hibernate ConnectionProvider (and borrowing from Hibernate 4.2 internal classes to implement that ConnectionProvider), it should be possible to activate them with a custom JDBC Driver wrapper, which should prove more maintainable.