ESP32-C2 has a single group timer, thus it will use it for the interrupt watchdog,
which is more critical than the task watchdog. The latter is implement in
software thanks to the `esp_timer`component.
This commit moidifies the TWDT as follows:
- Adds a feature to allows subscribing arbitrary users to the TWDT
- Changes esp_task_wdt_init() API to accept configuration structure
- Changes esp_task_wdt_init() and esp_task_wdt_deinit() to subscribe/unsubscribe
idle tasks of various cores.
- Adds support for SMP FreeRTOS idle tasks
- Updates startup code TWDT initialization
- Updates API documentation
This commit refactors the task watchdog as follows:
- Renamed variables, types, and functions
- Replaced manual linked list implementation with SLIST()
- Moved calloc()/free() calls out of critical sections
- Shortened ISR critical sections
- Updated API description
- Updated code formatting
