Replaces all instances of /turf/simulated/shuttle with simulated/wall/shuttle or simulated/floor/shuttle counterparts. (#7315)

Replaced all the snowflakey shuttle turfs with either /turf/simulated/wall/shuttle or /turf/simulated/floor/shuttle where I could, meaning shuttles are no longer indestructible but they can still take a lot of punishment.
    Added a few unsimulated turf variants to use on the cc z-level rather than having to use their simulated counterparts.
    Added smooth dark shuttle wall icons and a few more shuttle floor variants by AmoryBlaine.
    Fixed the dark shuttle corner blocks from looking weird after transit.
    A side effect of removing these shuttle turf types, conjure spells will now work inside of shuttles that used these removed turfs. Could perhaps be readded using areas if needed.

This is part 1 of the stuff from #5771 which will be split up and added in smaller batches beginning with adding the turf types with this pr.

code/modules/mining/mine_turfs.dm

@@ -11,8 +11,7 @@
 var/list/mineral_can_smooth_with = list(
 	/turf/simulated/mineral,
 	/turf/simulated/wall,
-	/turf/unsimulated/wall,
-	/turf/simulated/shuttle
+	/turf/unsimulated/wall
 )
 
 // Some extra types for the surface to keep things pretty.
@@ -167,6 +166,51 @@ var/list/mineral_can_smooth_with = list(
 		if(istype(M.selected,/obj/item/mecha_parts/mecha_equipment/tool/drill))
 			M.selected.action(src)
 
+//For use in non-station z-levels as decoration.
+/turf/unsimulated/mineral/asteroid
+	name = "rock"
+	icon = 'icons/turf/map_placeholders.dmi'
+	icon_state = "rock"
+	desc = "It's a greyish rock. Exciting."
+	opacity = 1
+	var/icon/actual_icon = 'icons/turf/smooth/rock_wall.dmi'
+	layer = 2.01
+	var/list/asteroid_can_smooth_with = list(
+		/turf/unsimulated/mineral,
+		/turf/unsimulated/mineral/asteroid
+	)
+	smooth = SMOOTH_MORE | SMOOTH_BORDER | SMOOTH_NO_CLEAR_ICON
+	smoothing_hints = SMOOTHHINT_CUT_F | SMOOTHHINT_ONLY_MATCH_TURF | SMOOTHHINT_TARGETS_NOT_UNIQUE
+
+/turf/unsimulated/mineral/asteroid/Initialize(mapload)
+	if (initialized)
+		crash_with("Warning: [src]([type]) initialized multiple times!")
+
+	if (icon != actual_icon)
+		icon = actual_icon
+
+	initialized = TRUE
+
+	turfs += src
+
+	if(dynamic_lighting)
+		luminosity = 0
+	else
+		luminosity = 1
+
+	has_opaque_atom = TRUE
+
+	if (smooth)
+		canSmoothWith = asteroid_can_smooth_with
+		pixel_x = -4
+		pixel_y = -4
+		queue_smooth(src)
+
+	if (!mapload)
+		queue_smooth_neighbors(src)
+
+	return INITIALIZE_HINT_NORMAL
+
 #define SPREAD(the_dir) \
 	if (prob(mineral.spread_chance)) {                              \
 		var/turf/simulated/mineral/target = get_step(src, the_dir); \
@@ -554,8 +598,7 @@ var/list/mineral_can_smooth_with = list(
 var/list/asteroid_floor_smooth = list(
 	/turf/unsimulated/floor/asteroid/ash,
 	/turf/simulated/mineral,
-	/turf/simulated/wall,
-	/turf/simulated/shuttle
+	/turf/simulated/wall
 )
 
 // Copypaste parent for performance.