boards: arm: Add support for the VBLUno51 board

+ VBLUno51 board
    nRF51822
    Bluetooth Low Energy
    DAPLink interface
    UNO pinout
    4 power

+ Wiki: https://vngiotlab.github.io/vbluno/



+ The following samples were tested:
    hello_world
    basic/button
    basic/blinky
    bluetooth/peripheral_hr
    bluetooth/beacon

Signed-off-by: Nam Do <robotden@gmail.com>
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>