Need to install RealTek RTL8812AU driver for Ubuntu Core 16

@ogra : I cannot revert this as the already integrated WLAN card is not giving me the required speed. Hence I need to get this installed.

@jalim : I see that you have also installed these drivers in ubuntu core 2 years ago. An instruction for the same would be much appreciated. Please note that I already have an integrated wifi card installed in the system. Do I need to disable that first to make this USB dongle work.