Workaround to disable bluetooth on NRF52 (#4055)

* Workaround to allow bluetooth disable on NRF52

* Use miminum tx power for bluetooth

* Reorganize

* Instantiate nrf52Bluetooth correctly..

* Change log message

src/platform/nrf52/NRF52Bluetooth.h

@@ -8,6 +8,7 @@ class NRF52Bluetooth : BluetoothApi
   public:
     void setup();
     void shutdown();
+    void startDisabled();
     void resumeAdvertising();
     void clearBonds();
     bool isConnected();