Uplink changes and additions (#1645)

* Splits uplink categories into separate files and moves other files around

* Corrects an incorrect description

* Puts uplink categories in uplink_categories into the same order as they are individual files

* Mercenaries now spawn with their own private uplink.

* Adds a random discount to uplink items that is applied every 15 minutes

no message

no message

* Adds changelog

* Fakes announcements are now once again purchasable from the uplink and actually work

* Removes a debug line

* Adds several existing items to the antag uplink including stun rounds for shotguns, metal foam grenades and more

* Refactors boxes.dm to use absolute pathing and for loops for contents

Adds changelog

code/datums/uplink/implants.dm

@@ -0,0 +1,25 @@
+/***********
+* Implants *
+***********/
+/datum/uplink_item/item/implants
+	category = /datum/uplink_category/implants
+
+/datum/uplink_item/item/implants/imp_freedom
+	name = "Freedom Implant"
+	item_cost = 3
+	path = /obj/item/weapon/storage/box/syndie_kit/imp_freedom
+
+/datum/uplink_item/item/implants/imp_compress
+	name = "Compressed Matter Implant"
+	item_cost = 4
+	path = /obj/item/weapon/storage/box/syndie_kit/imp_compress
+
+/datum/uplink_item/item/implants/imp_explosive
+	name = "Explosive Implant (DANGER!)"
+	item_cost = 6
+	path = /obj/item/weapon/storage/box/syndie_kit/imp_explosive
+
+/datum/uplink_item/item/implants/imp_uplink
+	name = "Uplink Implant" //Original name: "Uplink Implant (Contains 5 Telecrystals)"
+	item_cost = 5 //Original cost: 10
+	path = /obj/item/weapon/storage/box/syndie_kit/imp_uplink