Setting to Swap Confirm and Cancel in menu

[bagelbyheart]

Many people has strong associations with which face buttons will act as Confirm and Cancel with two typical layouts:

• Japanese: Bottom button cancels, right button confirms.
• Western: Bottom button confirms, right button cancels.

Previously ludo defaulted to the Japanese layout with no convenient means of swapping them. This pull request does the following:

• Adds the toggle Settings > Swap Confirm and Cancel
• When this toggle is set to true, input handling is switched to the Western layout.
• Hints update for gamepad or keyboard.

This would address libretro/ludo#501 and also includes the fixes included in libretro/ludo#521.