Convert EJB3 subsystem transformers to use chained transformers

The EJB3 subsystem defines its subsystem transformers in the class org.jboss.as.ejb3.subsystem.EJBTransformers.
This class organizes transformers in 'the old way' (see https://docs.jboss.org/author/display/WFLY/Domain+Mode+Subsystem+Transformers#DomainModeSubsystemTransformers-Chainedtransformers), so that there is a lot of code duplication.

This issue will reorganize the transformers to use the chained transformer technique, where only the changes from the current version to the most recent legacy version need be specified.