Added west.yaml file, that manages zephyr repo and its dependencies.
Additionally west manifest may now control sof submodules.
Added submanifests directory with README.txt file so the
submanifests directory exists in version control - otherwise
west update command returns error. This is bug described in
https://github.com/zephyrproject-rtos/west/issues/594 .
Co-developed-by: Andrey Borisovich <andrey.borisovich@intel.com>
Signed-off-by: Andrey Borisovich <andrey.borisovich@intel.com>
Signed-off-by: Krzysztof Frydryk <krzysztofx.frydryk@intel.com>