v1.8.0: Audio 代码重构与低功耗优化 (#943)

* Reconstruct Audio Code

* Remove old IoT implementation

* Add MQTT-UDP documentation

* OTA升级失败时，可以继续使用

main/boards/otto-robot/otto_robot.cc

@@ -7,11 +7,10 @@
 #include <wifi_station.h>
 
 #include "application.h"
-#include "audio_codecs/no_audio_codec.h"
+#include "codecs/no_audio_codec.h"
 #include "button.h"
 #include "config.h"
 #include "display/lcd_display.h"
-#include "iot/thing_manager.h"
 #include "lamp_controller.h"
 #include "led/single_led.h"
 #include "mcp_server.h"