add some faction mech discounts (#4139)

## Changelog

:cl:
balance: cybersun now gets discounts on cybersun mech designs. clip gets
a discount on the Durand for the same reason
/:cl:

code/modules/cargo/packs/mechs.dm

@@ -53,6 +53,8 @@ Build Your Own Suit
 		/obj/item/circuitboard/mecha/odysseus/main
 		)
 	crate_name = "202r Construction Kit"
+	faction = /datum/faction/syndicate/cybersun
+	faction_discount = 40
 
 /datum/supply_pack/mech/gygax_parts
 	name = "501p construction kit"
@@ -72,6 +74,8 @@ Build Your Own Suit
 		/obj/item/circuitboard/mecha/gygax/targeting
 	)
 	crate_name = "501p Construction Kit"
+	faction = /datum/faction/syndicate/cybersun
+	faction_discount = 40
 
 /datum/supply_pack/mech/mpgygax_parts
 	name = "NT-501p-MP construction kit"
@@ -112,6 +116,8 @@ Build Your Own Suit
 		/obj/item/circuitboard/mecha/durand/targeting
 	)
 	crate_name = "Durand Construction Kit"
+	faction = /datum/faction/clip
+	faction_discount = 20
 
 /*
 Mech Equipment