Use number instead of string for weapon slot type in configs

This is consistent with the rest of the weapon configs.

It also avoids issues with using isNumber or getNumber to check slot
type in scripts.

SQF/dayz_code/Configs/CfgWeapons/Weapon/LMG/M60A4.hpp

@@ -1,4 +1,4 @@
 class M60A4_EP1;
 class M60A4_EP1_DZE : M60A4_EP1 {
-    type = "1";
+    type = WeaponSlotPrimary;
 };