Now all warnings are disabled on SDK files, and enabled on our
application's files.
Fixed a couple of things in nRF52 which were unnoticed because all
warnings were disabled there from the beginning.
PUBLISHED_FROM=a33ab22d0ce85efea364b80478986b88f4b0a3a2
By making dir hierarchy replicate that of examples provided with the nRF
IoT SDK.
Also, example for Keil uVision IDE is added.
PUBLISHED_FROM=1a3d9a54d15eb1acfb1b5d162138576a387ed21c