umd0 solution: Add "OnlyEntireISOFileSystem" to fix #6638

Wraps around an ISOFileSystem, redirecting all the filenames to "" to achieve the desired effect (should fix Bleach Soul Carnival 2 without resorting to CPkmn's hack from #6638)

This is for discussion to begin with, I'm not sure this is the best solution.

Probably breaks savestates as-is... I'm actually confused by our MetaFileSystem::DoState , seems like it may store a system multiple times if it's mounted on several points.

Also, a nicer name for the class would be good...