WM1110 SDK kit enter serial DFU and add deployment packages (#4266)

* Switch default upload protocol to nrfutil so that pio generates zip deploy packages

* Enter serial DFU on SDK board

* Remove guard for DFU zip from SDK build

* NRF_USE_SERIAL_DFU macro instead

src/platform/nrf52/main-nrf52.cpp

@@ -286,5 +286,10 @@ void clearBonds()
 
 void enterDfuMode()
 {
+// SDK kit does not have native USB like almost all other NRF52 boards
+#ifdef NRF_USE_SERIAL_DFU
+    enterSerialDfu();
+#else
     enterUf2Dfu();
+#endif
 }