v1.8.0 to use Ethernet_Generic library

### Releases v1.8.0

1. Use new [Ethernet_Generic library](https://github.com/khoih-prog/Ethernet_Generic) as default for W5x00.
2. Rewrite to avoid `multiple-definitions` linker error for multiple-file project
3. Add example [multiFileProject](examples/multiFileProject) to demo how to avoid `multiple-definitions` linker error for multiple-file project
4. Update `Packages' Patches`

Author: khoih-prog

src/SSLClient/SSLClient.h

@@ -20,6 +20,9 @@
 
 #pragma once
 
+#ifndef SSL_CLIENT_H
+#define SSL_CLIENT_H
+
 #include "Client.h"
 #include "SSLClient/SSLSession.h"
 #include "SSLClient/SSLClientParameters.h"
@@ -526,4 +529,4 @@ class EthernetSSLClient : public Client
     unsigned m_br_last_state;
 };
 
-#include "SSLClient/SSLClient_Impl.h"
+#endif  // SSL_CLIENT_H

src/SSLClient/SSLClient_Impl.h

@@ -20,8 +20,10 @@
 
 #pragma once
 
+#ifndef SSL_CLIENT_IMPL_H
+#define SSL_CLIENT_IMPL_H
+
 #include "detail/Debug.h"
-//#include "SSLClient/SSLClient.h"
 
 /* see SSLClient.h */
 EthernetSSLClient::EthernetSSLClient(   Client& client,
@@ -1096,3 +1098,5 @@ void EthernetSSLClient::m_print_br_state(const unsigned state, const DebugLevel
       Serial.println("   RECVAPP");
   }
 }
+
+#endif  // SSL_CLIENT_IMPL_H