Corrects comments where talk about people or users rather than pets.

Now, it is checked whether the negative idOwner correctly throws the exception IllegalArgumentException.

- The authentication header has been added to the test of modifying a person's name.
- Updated the name of the PetDAO class to PetsDAO in the Pets resource.

Changed the attribute breed by specie.
In addition, there are changes in the script that has the lines to build the DB.

- Created the pet table
- Created the pet class