Application ui exercise - initial pull request

Here is my initial cut at Exercise 3.

It was created while using OJB as the persistence framework. I see we have since moved to JPA.
Also, there are a few file conflicts.
If desired, I could merge or rebase ?? my repo, and then re-submit the pull request to make it easier.

Also worth noting.
1. TrainingApplicationController.refreshQuestions() method has the solution.
In my next iteration, I will add TODOs: and stub out the solution. As it's part of the exercise to implement the method.  Instead of having them write the code from scratch, I thought I'd make it an "uncomment" exercise for the step of modifying the controller. Explaining the code as the students uncomment it.
2. TrainingApplicationView.xml  also contains part of the solution.
The "Training-Questions" section bean of the MaintenanceView contains properties "conditionalRefresh" and "methodToCallOnRefresh" which are to be added by the students during one of the exercise steps.