Changes

Fixes some errors in UserEJB.
The @Stateless annotation was added to the EJB. In the method
registerUser was added a Registration persist. Now, the userConfirmation
method doesnt recieve any param and looks for the Registration User in
the DB using the UUID recieved in the request link.

Adds some changes in UserEJB.
The registerUser and userConfirmation methods were modified to fix some
errors.