samples: boards: nrf: Add sample using Coresight STM on nrf54h20

Add sample that demonstrates logging using Coresight STM and ETR buffer
handled by the application core. Application is using sysbuild and 2
cores: cpuapp and cpurad. cpuapp is logging to STM and handling ETR buffer
where data from STM is collected and cpurad is only logging to STM.

Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>