Misc/Util: Add a template function for returning a random element from any container

src/server/game/Entities/Unit/Unit.cpp

@@ -14938,9 +14938,7 @@ Unit* Unit::SelectNearbyTarget(float dist) const
         return NULL;
 
     // select random
-    std::list<Unit*>::const_iterator tcIter = targets.begin();
-    std::advance(tcIter, urand(0, targets.size()-1));
-    return *tcIter;
+    return SelectRandomContainerElement(targets);
 }
 
 void Unit::ApplyAttackTimePercentMod(WeaponAttackType att, float val, bool apply)