examples: Add CMake + Open IoT SDK support

This demonstrates how a user creates a CMake project that
* gets Arm-2D and its dependencies using the Open IoT SDK
* creates applications that use and link against Arm-2D
* gets platform support from an MCU-Driver-HAL implementation, in this
case mcu-driver-reference-platforms-for-arm.

Signed-off-by: Lingkai Dong <lingkai.dong@arm.com>