[Feature Request] RAHasher - Support for RVZ format when hashing Wii/GameCube files

Now that the platform is live, would be beneficial to add support for RVZ mounting and reading so that external frontends using RAHasher can detect files correctly.

No public library in C/C++ that I can see, so may need to be taken from Dolphin's implementation. 

https://github.com/dolphin-emu/dolphin/blob/master/Source/Core/DiscIO/WIABlob.h