Kernel: Add a NetworkTask and a received network packet queue.

It will be easier to deal with incoming packets in a separate task.

Kernel/NetworkAdapter.cpp

@@ -21,3 +21,17 @@ void NetworkAdapter::send(const MACAddress& destination, const ARPPacket& packet
     send_raw((byte*)eth, size_in_bytes);
     kfree(eth);
 }
+
+void NetworkAdapter::did_receive(const byte* data, int length)
+{
+    InterruptDisabler disabler;
+    m_packet_queue.append(ByteBuffer::copy(data, length));
+}
+
+ByteBuffer NetworkAdapter::dequeue_packet()
+{
+    InterruptDisabler disabler;
+    if (m_packet_queue.is_empty())
+        return { };
+    return m_packet_queue.take_first();
+}