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/game/objects/structures/window.dm

@@ -11,6 +11,7 @@
 	icon_state = "window"
 	alpha = 196
 	density = TRUE
+	pass_flags_self = PASSWINDOW
 	w_class = WEIGHT_CLASS_NORMAL
 	layer = SIDE_WINDOW_LAYER
 	anchored = TRUE