example/system: add generic apptrace example with pytest support

examples/system/app_trace_basic/main/CMakeLists.txt

@@ -0,0 +1,2 @@
+idf_component_register(SRCS "app_trace_basic_example_main.c"
+                    INCLUDE_DIRS ".")

examples/system/app_trace_basic/main/app_trace_basic_example_main.c

@@ -0,0 +1,46 @@
+/*
+ * SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+/* Application Trace Basic Example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "esp_app_trace.h"
+#include "esp_log.h"
+
+static const char *TAG = "example";
+
+void app_main(void)
+{
+    ESP_LOGI(TAG, "Waiting for OpenOCD connection");
+
+    while (!esp_apptrace_host_is_connected(ESP_APPTRACE_DEST_JTAG)) {
+        vTaskDelay(1);
+    }
+
+    ESP_LOGI(TAG, "Sending example data to the host...");
+
+    for (unsigned int cnt = 1; cnt < 51; ++cnt) {
+        char buf[32] = {0};
+        snprintf(buf, sizeof(buf), "Apptrace test data[%d]:%d\n", cnt, cnt * cnt);
+        esp_err_t res = esp_apptrace_write(ESP_APPTRACE_DEST_JTAG, buf, strlen(buf), ESP_APPTRACE_TMO_INFINITE);
+        if (res != ESP_OK) {
+            ESP_LOGE(TAG, "Failed to write data to host [0x%x] (%s)", res, esp_err_to_name(res));
+        }
+        esp_apptrace_flush(ESP_APPTRACE_DEST_JTAG, 1000);
+        vTaskDelay(50 / portTICK_PERIOD_MS);
+    }
+
+    ESP_LOGI(TAG, "Done!");
+}