Device: Implement Ethernet PHY MDIO Communication

The following fixups were added during the squash/merge:

Fix formatting in EthPhyMessage and EthPhyRegPacket
Device: Use std::make_shared when creating the EthPHYControl filter
Network: Create NetID String for EthPHYControl
EthPhyRegPacket: Constants in PascalCase

communication/message/ethphymessage.cpp

@@ -0,0 +1,50 @@
+#include "icsneo/communication/message/ethphymessage.h"
+
+namespace icsneo
+{
+bool EthPhyMessage::appendPhyMessage(bool writeEnable, bool clause45, uint8_t phyAddrOrPort, uint8_t pageOrDevice, uint16_t regAddr, uint16_t regVal, bool enabled)
+{
+	auto msg = std::make_shared<PhyMessage>();
+	msg->Clause45Enable = clause45;
+	msg->Enabled = enabled;
+	msg->WriteEnable = writeEnable;
+	msg->version = 1u;
+	if( (FiveBits < phyAddrOrPort) ||
+		(clause45 && (FiveBits < pageOrDevice)) ||
+		(!clause45 && (FiveBits < regAddr)) )
+	{
+		return false;
+	}
+
+	if(clause45)
+	{
+		msg->clause45.port    = phyAddrOrPort;
+		msg->clause45.device  = pageOrDevice;
+		msg->clause45.regAddr = regAddr;
+		msg->clause45.regVal  = regVal;
+	}
+	else
+	{
+		msg->clause22.phyAddr = phyAddrOrPort;
+		msg->clause22.page    = pageOrDevice;
+		msg->clause22.regAddr = regAddr;
+		msg->clause22.regVal  = regVal;
+	}
+	return appendPhyMessage(msg);
+}
+
+bool EthPhyMessage::appendPhyMessage(std::shared_ptr<PhyMessage> message)
+{
+	if(message != nullptr)
+	{
+		messages.push_back(message);
+		return true;
+	}
+	return false;
+}
+
+size_t EthPhyMessage::getMessageCount() const
+{
+	return messages.size();
+}
+}