Moved fighting code into a component

All damage dealing is now handeled via FightingComponent.
Monsters use a derived MonsterFightingComponent since they can have a damage
mutation and have a seperate script callback.

The wirering with Being is still not optional since most of the stuff does
not exist as components.

Things done:
 - Seperated the fighting code from Being and only let Characters and Monsters
   add the Component (less overhead for npcs)
 - Added a getter for Attribute values to prevent searching it all the time in
   non Being members
 - Fixed the type if the damage mutation to double (no idea why it was int)
   I did not want to copy it over incorrectly
 - Removed the addAttack/removeAttack overrides in Character and made the
   knuckleAttack being added based on newly added signals

Future TODOS:
 - Remove depedency on Being as soon all needed dependencies are available
   as components of Entity
 - Move the monster script callback into the general fightingcomponent and
   make it usuable for characters too