GCN/Wii: Add support for GCZ and WDF formats

[GerbilSoft]

Issue #19 was closed because most of the formats were implemented. These formats have not been implemented yet:

• GCZ: Similar to CISO, but uses gzip compression. Supported by Dolphin Emulator.
• WDF: A significantly more complex sparse format than either CISO or WBFS. Not seen too often.

WIA is partially implemented. Full implementation requires LZMA decompression, which is probably too complicated for rom-properties.

[GerbilSoft]

GCZ is implemented as of commit 076db5edfbed51532f16c83ca3b6cc8530bb804f.

WDF, WIA, and the new RVZ format are still TODO.

[Maingron]

@GerbilSoft

Unsure about the state and if I should create a new issue, since .rvz does at least show some metadata, but it's missing quite a lot. Noticed that when I wanted to check for the region code. .rvz should not be too uncommon in the future, since it brings way better compression than any of .iso,.wbfs,.gcz,etc. Screenshots for comparison.

[GerbilSoft]

For .rvz, it currently only reads the uncompressed copy of the disc image header. I do plan on adding support for reading the compressed data, but it's significantly more complicated than the other formats. (It's around the same as .wia, but with different handling for garbage data; garbage data handling isn't too important for rom-properties though.)