Nordic "nRF52840 Dongle" Support

Update: it works well on nRF52840DK, but I had to follow @the1laz steps first:

cd targetlibs/nrf5x_15/
wget https://developer.nordicsemi.com/nRF5_SD­K/nRF5_SDK_v15.x.x/nRF5_SDK_15.0.0_a5364­1a.zip
unzip nRF5_SDK_15.0.0_a53641a.zip
mv nRF5_SDK_15.0.0_a53641a/* .
rm -rf nRF5_SDK_15.0.0_a53641a nRF5_SDK_15.0.0_a53641a.zip
git apply patches/*
rm -rf external/micro-ecc
cp -Rp ../nrf5x_12/external/micro-ecc external/micro-ecc
sed -i '/#include <nrfx\.h>/a # define NRFX_UARTE_ENABLED 0' integration/nrfx/legacy/nrf_drv_uart.h

and then compile:

make -DBOARD=NRF52840DK

The firmware seems functional, with one caveat - it won't advertise the board name nor the UART service, making it unconnectable from Espruino Web IDE. After patching the Web IDE to use the acceptAllDevices options I was able to connect to it from the IDE as well.