Baystation12 merchant port (#3155)

Port of the merchant mechanics from baystation12.
All of the trader, prices and most essential system are done, as well the job datum and the like. Mapping the shuttle, the base and a new dock will be done in a later pr.
Also adds phazon construction and several other items used in this pr.
The chance of the merchant slow being open at round start can be changed via the config, it is 20% by default.

code/_helpers/global_lists.dm

@@ -76,7 +76,7 @@ var/global/list/socks_m = list(
 
 	//Backpacks
 var/global/list/backbaglist = list("Nothing", "Backpack", "Satchel", "Satchel Alt", "Duffel Bag")
-var/global/list/exclude_jobs = list(/datum/job/ai,/datum/job/cyborg)
+var/global/list/exclude_jobs = list(/datum/job/ai,/datum/job/cyborg, /datum/job/merchant)
 
 // Visual nets
 var/list/datum/visualnet/visual_nets = list()
@@ -133,7 +133,7 @@ var/global/list/cloaking_devices = list()
 	sortTim(facial_hair_styles_male_list, /proc/cmp_text_asc)
 	sortTim(facial_hair_styles_female_list, /proc/cmp_text_asc)
 
-	//Body markings 
+	//Body markings
 	paths = subtypesof(/datum/sprite_accessory/marking)
 	for(var/path in paths)
 		var/datum/sprite_accessory/marking/M = new path()
@@ -180,7 +180,7 @@ var/global/list/cloaking_devices = list()
 	// The other lists are generated *after* we sort the main one so they don't need sorting too.
 	for (var/thing in all_species)
 		var/datum/species/S = all_species[thing]
-		
+
 		if (!(S.spawn_flags & IS_RESTRICTED))
 			playable_species += S.name
 		if(S.spawn_flags & IS_WHITELISTED)