KeepKey: Fix device enumeration on Windows 10 build 1903
KeepKey: Fix device enumeration on Windows 10 build 1903

Starting with Windows 10 build 1903 HID enumeration using cython-hidapi
is broken for KeepKey.
To work around this we register an enumerate function with the device
manager that uses keepkeylib's WebUsbTransport.enumerate to get the
connected devices. This uses libusb to do the enumeration is not affected.

fyookball/electrum,fyookball/electrum,fyookball/electrum