Add cooking oil, nutraslop, and beer keg to cargo supply packs (#93083)

## About The Pull Request
This adds the cooking oil vat, nutraslop serving tray, and beer keg as
purchasable items from cargo. I also removed the anchored state from the
cooking oil and nutraslop so that they can be moved.

## Why It's Good For The Game
These objects had no method to be created in game. Allowing them to be
purchased via cargo should lead to more usage. I'd honestly love to see
the crew's reaction to a mean chef who decides to feed the entire crew
nothing but nutraslop for the shift.

## Changelog
🆑
add: Add cooking oil, nutraslop, and beer keg to cargo supply packs.
Nutraslop serving trays and cooking oil vats can now be pushed and
moved.
/🆑

code/modules/reagents/reagent_dispenser.dm

@@ -617,7 +617,6 @@ MAPPING_DIRECTIONAL_HELPERS(/obj/structure/reagent_dispensers/wall/virusfood, 30
 	name = "vat of cooking oil"
 	desc = "A huge metal vat with a tap on the front. Filled with cooking oil for use in frying food."
 	icon_state = "vat"
-	anchored = TRUE
 	reagent_id = /datum/reagent/consumable/nutriment/fat/oil
 	openable = TRUE
 
@@ -626,7 +625,6 @@ MAPPING_DIRECTIONAL_HELPERS(/obj/structure/reagent_dispensers/wall/virusfood, 30
 	desc = "A dish full of food slop for your bowl."
 	icon = 'icons/obj/service/kitchen.dmi'
 	icon_state = "serving"
-	anchored = TRUE
 	reagent_id = /datum/reagent/consumable/nutraslop
 
 /obj/structure/reagent_dispensers/plumbed