Add listenable setDamage event when Attribute set

[Alien314]

When merged this pull request will:

• Adds a setDamage event for mod/mission script compatibility to attributes/initAttributes.inc.sqf and context_actions fnc_repairVehicles.sqf

[mharis001]

setDamage is GA/GE. A local event probably makes the most sense (consumers can rebroadcast if needed). Also, the naming of this should be considered - should this be namespaced under common?

[Alien314]

Nearly every other event uses common, so I thought it was simplest since setDamage isn't necessarily an attribute specific thing. Edit: added event to context_actions fnc_repairVehicles as well.