Randoms Part 1 and also Corn - Random object sprites and corn tank changes. (#19975)

Added new sprites for random objects for everything in random/clothing,
/food, /loot, /medical, and /misc.
Also got distracted and changed how the corn oil/cooking oil tank looks
and how much reagent it holds. Now looks like the rest of the reagent
tanks and holds the same amount of liquid, 1000u.

code/game/objects/random/random.dm

@@ -1,8 +1,8 @@
 /obj/random
 	name = "random object"
 	desc = "This item type is used to spawn random objects at round-start"
-	icon = 'icons/misc/mark.dmi'
-	icon_state = "rup"
+	icon = 'icons/obj/random.dmi'
+	icon_state = "need-sprite"
 	var/spawn_nothing_percentage = 0 // this variable determines the likelyhood that this random object will not spawn anything
 	var/list/spawnlist
 	var/list/problist