unify activity detection in PhoneAPI, turn off BLE API while serial API in use

src/SerialConsole.cpp

@@ -1,5 +1,6 @@
 #include "SerialConsole.h"
 #include "configuration.h"
+#include "target_specific.h"
 #include <Arduino.h>
 
 #define Port Serial
@@ -34,4 +35,10 @@ void SerialConsole::handleToRadio(const uint8_t *buf, size_t len)
     canWrite = true;
 
     StreamAPI::handleToRadio(buf, len);
+}
+
+/// Hookable to find out when connection changes
+void SerialConsole::onConnectionChanged(bool connected)
+{
+    setBluetoothEnable(!connected); // To prevent user confusion, turn off bluetooth while using the serial port api
 }