Added debug inventory menu

scripts/Singleton/UI.gd

@@ -2,10 +2,12 @@ class_name UISystem extends Control
 
 var QUEST_MENU:QuestMenu
 var DEBUG_MENU:DebugMenu
+var INVENTORY_MENU:FullInventoryMenu
 
 func _ready() -> void:
 	QUEST_MENU = $QuestMenu
 	DEBUG_MENU = $DebugMenu
+	INVENTORY_MENU = $FullInventory
 
 func _process(delta: float) -> void:
 	# This needs to always be at the end of the parent node's tree