Added documentation about the ESP-IDF changes to FreeRTOS.
The documentation covers changes to the following FreeRTOS aspects.
- Task Creation
- Affects on scheduling (Task skipping, scheduler suspension, tick synchronicity)
- Critical sections and disabling interrupts
- Thread Local Storage Pointers and deletion callbacks
- Configuring ESP-IDF FreeRTOS
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
