Integration with log4j and i18n message bundles.

- Integrated with log4j. Added a vanilla log4j.properties file.
- Integrated with Spring MessageSource i18n bundles. Fixed an issue in
the Java-based Spring config with singleton beans. The Thymeleaf
template/view objects were not in the appropriate scope.
- Split the Java Configuration across multiple classes, based on an idea
I found in a credited Git repo.