Refactor page-object

• Solves Page-Object source placement? #524
• The goal here was to move all sources placed in src/test instead of src/main to be able to used the uml-reverse-mapper.

Pull request description :

• Create 2 Sub modules such as in the initial commit from @colinbut :

  • sample-application : that represents the sample application under test.
  • test-automation : that represents the test project which tests that sample application

• The second commit was to replace e.printStackTrace with a Logger like recommanded by Sonar.

PS : I update the root pom.xml to remove the scope "test" under net.sourceforge.htmlunit because now we need it for the test-automation src/main folder.