AdventureArenas

Restored content:

Adds six unused Arenas, both in the "Duel" mode and on the "adventure map", where they can now randomly appear in the corresponding biomes.
Author's translation:
1) Abandoned Mine
2) Swamp Mire
3) Velvet Meadow
4) Blazing Wasteland
5) Lifeless Sands
6) Treasure Dungeon
Thanks to Rommy for the support provided.