add NetworkUtil, move NetworkDeviceType to seperate file

src/enums/NetworkDeviceType.h

@@ -0,0 +1,16 @@
+#pragma once
+
+enum class NetworkDeviceType
+{
+    WiFi,
+    W5500,
+    W5500M5,
+    W5500M5S3,
+    Olimex_LAN8720,
+    WT32_LAN8720,
+    M5STACK_PoESP32_Unit,
+    LilyGO_T_ETH_POE,
+    GL_S10,
+    ETH01_Evo,
+    CUSTOM
+};