Update Spring sample application

Prior to this commit, the sample application used for Techempower
benchmarks was using spring-framework 3.2.1, manually managing
Hibernate sessions, and old app configuration.

This commit updates this sample application.
Spring projects were added/updated:
* Spring-Framework 4.0.0.RC1
* Spring Boot
* Spring Data JPA

Application layout was updated as well, using:
* Spring Boot App launcher
* Spring Data repositories
* Full Java Configuration
Simplified boot application
Rollback to a more optimal Spring Boot application

The application now run within an executable JAR
and uses Spring Boot's defaults for configuration.

Benchmark setup code and configuration have been updated to reflect those changes.