Add option to swap confirm/cancel buttons

[MandL27]

Almost posted this as a comment in #533 before deciding it'd fit better as its own issue.

source

The Japanese release of Unleashed on PS3 uses Circle to confirm and Cross to cancel, as was common for PS3 games. While this would be superseded by the planned more robust input remapping, this particular example is a vanilla feature, and other version-specific features like the Japanese logo are implemented at present.

[hyperbx]

The PS3 version also uses the Triangle button to go back in some menus (e.g. the Go to the capital / Select stage menu).

[MandL27]

So there's three competing controller standards instead of two. Joy. I hadn't checked EN PS3, though given my EN PS2 library seems to flipflop between Circle or Triangle to cancel, I can't say I'm surprised.

More relevant to the topic at hand, would (should?) this be all-or-nothing for adding the other menu mappings? At least to me, it wouldn't make much sense to single out one PS3 mapping over the other for inclusion, even if that one would benefit Nintendo controller users.