Update SSOverlays (ported from Baystation) (#19051)

Our SSOverlays system is outdated, and is likely the cause of many of
the issues seen in #18895. It has also been linked to a massive server
performance decrease.

This brings an updated system from Baystation, hopefully with speed
increases.

Should be testmerged, ideally with #18895.

---------

Co-authored-by: Cody Brittain <cbrittain10@live.com>

code/modules/modular_computers/file_system/programs/civilian/cargo_control.dm

@@ -219,7 +219,7 @@
 					if(!P.stamped)
 						P.stamped = new
 					P.stamped += /obj/item/stamp
-					P.add_overlay(stampoverlay)
+					P.AddOverlays(stampoverlay)
 					P.stamps += "<HR><i>This paper has been stamped by the Shipping Server.</i>"
 					computer.visible_message(SPAN_NOTICE("\The [computer] prints out paper."))
 		if("bounty_print")