Changes

tsk40 Adds REST method to delete user microstories
Updated security access in the web.xml file in order to allow DELETE and
POST methods to interact with the application.
Added REST method to delete the microstories of the logged-in user. It
was needed to update the related EJB method to check if the logged-in
user was the author of the story to delete.
Added a new test to check the functionality of the REST method. This
test uses a new dataset that stores the remining stories.