The project configuration has been simplified by unifying some part of
the mysql and h2 configurations.

In addition, the project has been configured to allow the execution of
the application with the Maven WildFly plugin.

The REST layer has been added but with incomplete tests. Students will
have to complete the tests.

This commit includes an important refactorization regarding tests. Test
classes and datasets have been moved from the "service" project to a new
"tests" project. This way, any project can include this "tests" project
as a dependency in order to have access to these common testing
resources.