debug-console: set overlay to enable shell/console over USB (CDC ACM)

currently shell and console is not working via USB, instead one have to use the UART interface and use a serial to USB cable to access the arduino shell.

With this overlay configuration we are able to access the arduino shell using the USB port of the arduino. Also, we have to enable CONFIG_USB_DEVICE_STACK in prj.conf and call usb_enable() from the source.

Signed-off-by: Francesco Pham francesco.pham@huawei.com