Add new duel type : mma, check for age when two sorcerer have the same caracteristic and refactor the code to help readability

• Added the mma duel type
• the age is check as a last reasort if the sorceres have the same statistics
• refactoring of the code :
  • Added a DatabaseHandler to access the db and avoid any sql in Service/Controller
  • Refactor the code to avoid complexity in methods
  • Added tests
  • Change spells map in Values.java to Spells.java as an enum
  • Changed duel type to an enum