Added default sdkconfig for qemu build for the mqtt publish example,
Added environment configuration for running the same test on target
or in qemu
Updated missing example tests per latest ttfw refactoring
Implements support for system level traces compatible with SEGGER
SystemView tool on top of ESP32 application tracing module.
That kind of traces can help to analyse program's behaviour.
SystemView can show timeline of tasks/ISRs execution, context switches,
statistics related to the CPUs' load distribution etc.
Also this commit adds useful feature to ESP32 application tracing module:
- Trace data buffering is implemented to handle temporary peaks of events load