Kernel: Start adding support for E1000 network adapters.

Kernel/NetworkAdapter.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <AK/Types.h>
+
+class NetworkAdapter {
+public:
+    virtual ~NetworkAdapter();
+
+    virtual const char* class_name() const = 0;
+    const byte* mac_address() { return m_mac_address; }
+
+protected:
+    NetworkAdapter();
+    void set_mac_address(const byte*);
+
+private:
+    byte m_mac_address[6];
+};