LttP: Rename Shop Slot 1, 2, 3 to Shop Slot Left, Center, Right

General: Move generic IDs from LttP to new Generic World
Generate: ensure thread errors are collected before data from their completion may be referenced in playthrough/spoiler

BaseClasses.py

@@ -911,7 +911,8 @@ class Boss():
         return f"Boss({self.name})"
 
 class Location():
-    shop_slot: bool = False
+    # If given as integer, then this is the shop's inventory index
+    shop_slot: Optional[int] = None
     shop_slot_disabled: bool = False
     event: bool = False
     locked: bool = False