Add objectives listing and all four data disks/tablets.

Track each individual disk and ensure they are loaded in order.
Player can collect multiple disks in one run but must present them
to the pharaoh in order.

pharaoh.gd

@@ -1,6 +1,6 @@
 extends Interactable
 
-var disks_wanted = [1, 2, 3, 4, 5]
+var disks_wanted = [1, 2, 3, 4]
 var disks_loaded = []
 
 func _ready() -> void:
@@ -15,8 +15,18 @@ func load_disk(disk_num: int) -> bool:
 	return true
 
 func _on_interacted() -> void:
-	var disk_num = %Player2D.take_disk()
-	if not load_disk(disk_num):
+	var wanted_disk = disks_wanted.front()
+	if not %Player2D.take_disk(wanted_disk):
 		return
 
-	print("Loaded up disk ", disk_num)
+	if not load_disk(wanted_disk):
+		return
+
+	%Player2D.complete_objective("disk%d" % wanted_disk)
+	print("Loaded up disk ", wanted_disk)
+
+	wanted_disk = disks_wanted.front()
+	if not wanted_disk:
+		return
+
+	%Player2D.give_objective("disk%d" % wanted_disk, "Locate data disk %d" % wanted_disk)