[DNM][DNM][WIP] Projectile backend code port and update

Ports#54924,  #65061, #59804 from /tg.
adds auxiliary code from /tg to make code work.

code/game/objects/structures/transit_tubes/transit_tube.dm

@@ -8,17 +8,13 @@
 	layer = LOW_ITEM_LAYER
 	anchored = TRUE
 	climbable = 1
+	pass_flags_self = PASSGLASS
 	var/tube_construction = /obj/structure/c_transit_tube
 	var/list/tube_dirs //list of directions this tube section can connect to.
 	var/exit_delay = 1
 	var/enter_delay = 0
 	var/const/time_to_unwrench = 2 SECONDS
 
-/obj/structure/transit_tube/CanPass(atom/movable/mover, turf/target)
-	if(istype(mover) && (mover.pass_flags & PASSGLASS))
-		return 1
-	return !density
-
 /obj/structure/transit_tube/New(loc, newdirection)
 	..(loc)
 	if(newdirection)