moves abstract_type up to datum, spawners wont spawn them (#92909)

## About The Pull Request
moves all implementations (im aware of) for "Im a parent type dont spawn
me please" to the datum layer to standardized behavior
adds a standerized proc for filtering out "bad" items that we dont want
spawning. applies to it the subtype vendor, gifts, and a new spawner and
mystery box for a random gun (neither playerfacing)
"port" of https://github.com/shiptest-ss13/Shiptest/pull/4621



https://github.com/user-attachments/assets/22f6f0b2-b44e-411a-b3dc-6b97dc0287aa

small warning: I dont have EVERY abstract type defined right now but,
ive done a good enough job for now. Im tired of data entry rn
## Why It's Good For The Game
standardizing behavior. Might be a micro hit to performance however

having this lets us not rely on icon state to determine whether
something is a parent type and makes it much easier to tell something is
a parent type (could be applied further to things like admin spawning
menus and things like that).

need feedback on if this is actually good for the game.
## Changelog
🆑
add: Soda cans show up in the silver slime drink table.
add: Examine tag for items that are not mean to show up ingame.
refactor: Standardizes how gifts rule out abstract types.
fix: gifts no longer check if something has an inhand, massively
expanding the list of potential items.
/🆑

code/modules/reagents/reagent_containers/applicator.dm

@@ -2,6 +2,7 @@
 /obj/item/reagent_containers/applicator
 	name = "generic reagent applicator"
 	desc = "Report this please."
+	abstract_type = /obj/item/reagent_containers/applicator
 	has_variable_transfer_amount = FALSE
 	grind_results = list()
 	/// Action string displayed in vis_message

code/modules/reagents/reagent_containers/cups/_cup.dm

@@ -1,5 +1,6 @@
 /obj/item/reagent_containers/cup
 	name = "open container"
+	abstract_type = /obj/item/reagent_containers/cup
 	amount_per_transfer_from_this = 10
 	possible_transfer_amounts = list(5, 10, 15, 20, 25, 30, 50)
 	volume = 50

code/modules/reagents/reagent_containers/cups/drinks.dm

@@ -6,6 +6,7 @@
 	desc = "yummy"
 	icon = 'icons/obj/drinks/drinks.dmi'
 	icon_state = "glass_empty"
+	abstract_type = /obj/item/reagent_containers/cup/glass
 	possible_transfer_amounts = list(5,10,15,20,25,30,50)
 	resistance_flags = NONE
 

code/modules/reagents/reagent_containers/cups/soda.dm

@@ -11,6 +11,7 @@
 	icon = 'icons/obj/drinks/soda.dmi'
 	icon_state = "cola"
 	icon_state_preview = "cola"
+	abstract_type = /obj/item/reagent_containers/cup/soda_cans
 	reagent_flags = NONE
 	spillable = FALSE
 	custom_price = PAYCHECK_CREW * 0.9