This commit removes the usage of all legacy FreeRTOS data types that
are exposed via configENABLE_BACKWARD_COMPATIBILITY. Legacy types can
still be used by enabling CONFIG_FREERTOS_ENABLE_BACKWARD_COMPATIBILITY.
By using IOMUX instead of GPIO Matrix for UART, it is now possible
on ESP32 boards to use the UART as a wake up source even if it is
not used as a console.
For other boards where this issue was not present, using IOMUX has
the advantage to be faster than using GPIO matrix, so a highest
baudrate can be used
