Flags and adjacency work (#20259)

Added a bunch of flags for passflags on things that were previously
missing them.
Removed snowflake passthrow var, it's a passflag now.
Updated ClickCross and Adjacency code.
It's now possible to interact with things that are adjacent but
otherwise have a machine (or other appropriate items) blocking them, eg.
think of an APC on the wall with a machine in front of it.

code/modules/holodeck/HolodeckObjects.dm

@@ -331,9 +331,9 @@
 	desc = "Boom, Shakalaka!"
 	icon = 'icons/obj/basketball.dmi'
 	icon_state = "hoop"
-	anchored = 1
-	density = 1
-	throwpass = 1
+	anchored = TRUE
+	density = TRUE
+	pass_flags_self = PASSSTRUCTURE | LETPASSTHROW
 
 /obj/structure/holohoop/attackby(obj/item/attacking_item, mob/user)
 	if (istype(attacking_item, /obj/item/grab) && get_dist(src,user)<2)