Cite original inspiriation by Domain-Driven Design, but make clear the
flexible and general-purpose nature of Spring's stereotype annotations
such as @Repository and @Service.
Also update @Repository Javadoc with more explicit instructions about
switching on exception translation through use of
PersistenceExceptionTranslationPostProcessor, and update PETPP Javadoc
for style as well as concrete examples of 'resource factories' that
implement the PersistenceExceptionTranslator interface
Issue: SPR-8691
Chris Beams