Reduce Lists Memory usage, update CI (#17706)

* Convert alerts to a lazylist

* Convert fullscreens to lazylist

* Convert ckeys_allowed_itemspawn to a lazylist

* Convert camera lists to lazylists

* Get rid of an old unused footstep_sounds list

* Make flooring_cache a lazy list

* Fix flooring_blacklist, convert a bunch more flooring lists to lazylists

* Improve ci byond caching

code/modules/mob/living/carbon/human/life.dm

@@ -1407,7 +1407,8 @@
 
 	if(istype(client.eye,/obj/machinery/camera))
 		var/obj/machinery/camera/cam = client.eye
-		client.screen |= cam.client_huds
+		if(LAZYLEN(cam.client_huds))
+			client.screen |= cam.client_huds
 
 	if(stat == DEAD) //Dead
 		if(!druggy)		see_invisible = SEE_INVISIBLE_LEVEL_TWO

code/modules/mob/living/simple_mob/subtypes/animal/alien animals/stardog.dm

@@ -519,13 +519,6 @@
 
 	can_paint = TRUE
 
-	footstep_sounds = list("human" = list(
-		'sound/effects/footstep/carpet1.ogg',
-		'sound/effects/footstep/carpet2.ogg',
-		'sound/effects/footstep/carpet3.ogg',
-		'sound/effects/footstep/carpet4.ogg',
-		'sound/effects/footstep/carpet5.ogg'))
-
 /obj/structure/flora/tree/fur
 	name = "tall fur"
 	desc = "Tall stalks of fur block your path! Someone needs a trim!"