[MDB IGNORE] Make /obj/item/stamp abstract, create proper granted stamp subtype (#94139)

## About The Pull Request

There is technically an `/obj/item/stamp/granted` in that one traitor
objective refers to it and tries to override a proc on it thus making it
a valid type, but not really. This changes the base `/obj/item/stamp`
from being the granted stamp to being an abstract type, and creates a
proper subtype for the granted stamp.

## Why It's Good For The Game

Base types being concrete outside of scenarios where its intuitive are
very annoying

## Changelog
🆑
code: makes /obj/item/stamp abstract, creates /obj/item/stamp/granted
/🆑

code/modules/surgery/organs/internal/cyberimp/augments_arms.dm

@@ -287,7 +287,7 @@
 		/obj/item/taperecorder,
 		/obj/item/lighter,
 		/obj/item/laser_pointer,
-		/obj/item/stamp,
+		/obj/item/stamp/granted,
 		/obj/item/stamp/denied,
 	)