Changes

tsk72 Changes to protected visibility the constructors for testing
purposes
The constructors used for testing purposes on Story and User classes
have been changed to protected visibility because if they are public
could be used in code with not test purposes. For this changes, the
matchers and datasets for testing have been moved to the same package of
entities class to allow that the protected constructors can be accessed
from these classes. The package chosen to place these classes is called
"es.uvigo.esei.dgss.teama.microstories.domain.entities" and it has been
decided to include them in the entities subpackage because they share
the same objective and allow it to be isolated from new subpackages that
may appear in the "domain" package in the future.