test/BeanRepositoryTest: Tweak testWithDifferentTimeZones.
PersistentDateTimeAsOneString: Revert back to using DateTimeZoneWithOffset.
PersistentDateTimeAsOneString: Rename to start with variable name "dateTime".
PersistentDateTimeAsOneString: Use LocalDateTime.
test/BeanRepositoryTest: As timezone info isn't used for ordering, no longer require tests (dat fubar TDD).
Revert "Move from h2 to postgresql."

This reverts commit d04e6dc6547fbb3ba9a40c357aa3f1b9542d1f29.
test/BeanRepositoryTest: .. system default overrides and caching.. this is going to suck, forget it.
test/BeanRepositoryTest: Remove unused import.
test/BeanRepositoryTest: Remove unnecessary delete all.
config: Try to change from in-memory to mixed-mode.