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/common/ml307_board.cc

@@ -66,12 +66,6 @@ void Ml307Board::StartNetwork() {
     ESP_LOGI(TAG, "ML307 Revision: %s", module_revision.c_str());
     ESP_LOGI(TAG, "ML307 IMEI: %s", imei.c_str());
     ESP_LOGI(TAG, "ML307 ICCID: %s", iccid.c_str());
-
-    // Close all previous connections
-    modem_->ResetConnections();
-
-    // Enable sleep mode
-    modem_->SetSleepMode(true, 30);
 }
 
 NetworkInterface* Ml307Board::GetNetwork() {