Add support for the 8BitDo Ultimate 2 Bluetooth in DInput mode

[nadiaholmquist]

• I confirm that I am the author of this code and release it to the SDL project under the Zlib license. This contribution does not contain code from other sources, including code generated by a Large Language Model ("AI").

Description

Adds support for the DInput mode of the 8BitDo Ultimate 2 Bluetooth controller, not to be confused with the already-supported Ultimate 2 Wireless.

This controller is nearly identical to the Wireless variant, but has functionality for connecting to the Switch and Switch 2 over Bluetooth which the Wireless variant lacks. It also accordingly has the Nintendo-style face button layout.

The Bluetooth variant normally lacks a DInput mode, but there's a beta firmware for its 2.4G receiver which adds it and seems to make it behave identically to the Wireless version. I don't know if there's anywhere this firmware version can be downloaded outside of contacting 8BitDo's support, and whether there's a newer version than what I have. Rumble and motion sensors are not working, just like the code seems to imply it doesn't for older firmware versions of the Wireless variant, but one could hope that if a non-beta version of this firmware were ever to materialize, these features would be supported in it.

Existing Issue(s)

[slouken]

@8BitDo, can you please comment on whether SDL should officially support the beta firmware, and if not, when the final firmware is planned for release?