Let the template define the actor used for the projectile. Also let projectiles have an impact animation (such as an explosion).
This will enable us in the future to have technologies that change projectiles.
This is also somewhat of a refactoring.
Patch By: Mate-86
Reviewed By: wraitii
Trac Tickets: #1909
Differential Revision: https://code.wildfiregames.com/D945