[Feature Request] Mouse and keyboard support in Xbox Dev Mode UWP

[Roet-Ivar]

Description

Mouse and keyboard can be read by the xbox in selected apps that have the feature enabled, even the dev mode menu has it natively. RetroArch would greatly benefit from mouse/keyboard input in many ways (DOS, lightgun games, Wii, point-and-click adventure games etc).

Expected behavior

When connecting a HID compliant mouse and keyboard RetroArch should detect them as input devices.

Actual behavior

No keyboard or mouse are detected with either driver (UWP / xinput).

Steps to reproduce the bug

1. Connect mouse and keyboard
2. Verify that they work the dev mode menu
3. Start RetroArch
4. See if the input are detected or not