Adds esp_mqtt_cxx component

- Component moved from esp-idf
- Files moved to adjust to esp-protocol structure

components/esp_mqtt_cxx/examples/ssl/pytest_mqtt_ssl.py

@@ -0,0 +1,8 @@
+# SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: Unlicense OR CC0-1.0
+import pytest
+
+
+@pytest.mark.esp32
+def test_dummy() -> None:
+    pass