Wii classic controller and nunchuk support

[Anh302kay]

Adds Wii classic controller support. Buttons are inverted to be correct with the GUI. Analog sticks are supported now, deadzone might need adjusting. Tested on real hardware with snes classic controller. Also now supports the wii nunchuk, tested on real hardware.

[Mefiresu]

Thanks ! Though I believe the best way to implement the inverted buttons would be to use the custom settings available here: https://github.com/Rubberduckycooly/RSDKv5-Decompilation/blob/master/RSDKv5/RSDK/User/Core/UserCore.cpp#L319

It might be necessary to flip the Wiimote inputs too once these options are set. Could you research this ?

[Mefiresu]

Some feedback after testing mappings in general:

• The nunchuk analog's deadzone appears to be a bit low (might need to double check with other nunchuks) while classic's is fine
• Sideways Wiimote uses B to swap characters in Encore mode, which IMO is a bit hard to access in this configuration (swapping with the A button could be a better choice)

DEV: Now that there's effectively 3 different mappings, I feel like the variable names for button names can become confusing (RSDKv5 internally maps using Xbox-style controls with for example A to Confirm / B to Cancel). Maybe changing the variable names to fit their purpose would be clearer (so stateA could be stateConfirm, stateB could be stateCancel), or just writing comments in WiiInputDevice.hpp to explain their function in game. Diving a bit deeper into it made me realize that the confirmButtonFlip setting is actually useless, and adds confusion. This actually caused me problems at first because the value wouldn't be written to Settings.ini if the file already existed. ~~It also appears that the Switch version actually has Confirm on B and Cancel on A (which physically corresponds to an Xbox controller layout). To be more accurate to how the Switch controllers are mapped, I suggest removing the confirmButtonFlip changes and manually swapping stateA with stateB in every mapping.~~ (I was wrong, see next message)

[Mefiresu]

Nevermind about the Switch layout, the buttons are indeed flipped.

Also it seems like the confirmButtonFlip setting never gets set on first boot (when no Settings.ini exists yet), so something might be missing in the Load/Save Settings INI functions.