Provide SCP-compatible Extended XInput API

[nefarius]

Originally requested by @CookiePLMonster

About

ScpServer/ScpToolkit provided an XInput Proxy DLL which basically offloaded grabbing inputs and submitting rumble requests to the core of SCP via IPC mechanism.

It also introduced/exposed the additional API XInputGetExtended which provided a custom report structure to expose pressure axes as scaled easy to consume float values for any other project to consume without having to worry about the underlying implementation.

Why

I don't know, apparently some crazy folks adopted the API and want it back 😁

How

Provide a simple IPC mechanism between the driver and a new simple C/C++ based proxy DLL to make readout independent of the HID device mode and also forward vibration requests transparently.