Glass sliding doors for urban maps (#17448)

* doors

* adjustments and fix

code/game/objects/structures/urban.dm

@@ -677,7 +677,19 @@
 	else
 		return FALSE //Keys only
 
+/obj/machinery/door/urban/glass_sliding
+	name = "sliding glass door"
+	desc = "An electronic sliding glass door, often seen in cities."
+	icon_state = "glass_sliding_closed"
+	base_icon = "glass_sliding"
+	autoclose = TRUE
+	support_ids = TRUE
+	glass = TRUE
+	opacity = 0 //otherwise it is opaque until opened/closed for the first time.
 
+/obj/machinery/door/urban/glass_sliding/double //use north state for left side and south state for right side
+	icon_state = "double_glass_sliding_closed"
+	base_icon = "double_glass_sliding"
 
 /**
  * # Door keys