Add “At Most One Dungeon Reward per Hint Area” setting

[fenhl]

Multiple people have requested a variant of the dungeon reward shuffle setting where there can be a maximum of 1 dungeon reward in each hint area. This could be implemented as a separate toggle, displayed if dungeon rewards are set to “Overworld”, “Any Dungeon”, “Anywhere”, or “Regional” (where it would prevent a stone and its corresponding medallion from being placed in the same hint area).