ESP-IDF minimal Hello World example

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

extern "C" void app_main(void)
{
    // Minimal ESP-IDF Hello World example in a loop
    while (1) {
        printf("Hello world!\n");
        vTaskDelay(1000 / portTICK_PERIOD_MS);
    }
}