Persistent mobile liquid tanks (#22879)

# Summary

This PR makes liquid tanks (fuel, foam, water) persistent.

code/modules/cargo/bounties/assistant.dm

@@ -80,7 +80,7 @@
 	description = "Send us some water tanks that will be used for botany research, and definitely not for creating a slip 'n slide in %PERSONNAME's office."
 	reward_low = 115
 	reward_high = 135
-	required_count = 3
+	required_count = 1
 	random_count = 1
 	wanted_types = list(/obj/structure/reagent_dispensers/watertank)
 

code/modules/cargo/bounties/engineer.dm

@@ -54,7 +54,7 @@
 	description = "After observing your engineering staff, we think it's best if you send us a few of those fuel tanks so nobody hurts themselves."
 	reward_low = 250
 	reward_high = 350
-	required_count = 4
+	required_count = 1
 	random_count = 2
 	wanted_types = list(/obj/structure/reagent_dispensers/fueltank)
 

code/modules/cargo/items/engineering.dm

@@ -430,6 +430,20 @@
 	groupable = TRUE
 	spawn_amount = 1
 
+/singleton/cargo_item/extinguishertank
+	category = "engineering"
+	name = "extinguisher tank"
+	supplier = "hephaestus"
+	description = "A tank filled with extinguisher fluid."
+	price = 10
+	items = list(
+		/obj/structure/reagent_dispensers/extinguisher
+	)
+	access = ACCESS_ENGINE
+	container_type = "box"
+	groupable = TRUE
+	spawn_amount = 1
+
 /singleton/cargo_item/gasmask
 	category = "engineering"
 	name = "gas mask"

code/modules/cargo/items/miscellaneous.dm

@@ -72,3 +72,17 @@
 	container_type = "crate"
 	groupable = TRUE
 	spawn_amount = 1
+
+/singleton/cargo_item/watertank
+	category = "miscellaneous"
+	name = "water tank"
+	supplier = "orion"
+	description = "A tank filled with water."
+	price = 10
+	items = list(
+		/obj/structure/reagent_dispensers/watertank
+	)
+	access = 0
+	container_type = "box"
+	groupable = TRUE
+	spawn_amount = 1

code/modules/cargo/random_stock/large.dm

@@ -37,12 +37,6 @@ STOCK_ITEM_LARGE(bubbleshield, 0.5)
 			break
 	new /obj/structure/machinery/shield_capacitor(T)
 
-STOCK_ITEM_LARGE(watertank, 2)
-	new /obj/structure/reagent_dispensers/watertank(L)
-
-STOCK_ITEM_LARGE(fueltank, 2)
-	new /obj/structure/reagent_dispensers/fueltank(L)
-
 STOCK_ITEM_LARGE(lubetank, 2)
 	new /obj/structure/reagent_dispensers/lube(L)