Replace Agahnim item by an eleventh dungeon

[Ninban]

The main goal is to have the Castle Tower available as a dungeon to track in keysanity mode with its two small keys while combining Agahnim's status as a boss.

This also has the side-effect of including the dungeon on the location tracker. For now, it returns item availability according to normal modes, so it has no chests, just the boss itself. In the future there will be two chests available in the dungeon for keysanity logic.

You can test on my own firebase project: https://lttp-tracker-f0591.firebaseapp.com/

[stochaztic]

As is this will give errors when people try to use existing rooms (NaNs on smallkeys[11] from Firebase for example, and I think the default layout is expecting the agahnim item that no longer exists), Would you have time to look into ways to clean this up? I'm hesitant to merge this and break existing trackers, as most people probably aren't checking the changelog regularly.

[Ninban]

No problem, thanks for finding this out!
I'll probably be a bit busy in the following days, but I'm not in a hurry to merge.