feat(Clientlib): separate client encryption and server computation

Resolve #200

docs/cpp_api/clientlib/client_example.cpp

@@ -0,0 +1,16 @@
+#include <concretelang/ClientLib/ClientLambda.h>
+
+// Include the header that has been generated by the compiler
+#include "myinclude/fhe_service/additions.h"
+
+void query_server(MyConnection conn) {
+    auto libPath = "/opt/fhe_service/libs/additions.so";
+    std::ostream to_server = conn.ostream();
+    std::ostream from_server = conn.istream();
+    // In a real code only load once.
+    auto add2int = additions::add2int::load(libPath, seed_msb, seed_lsb);
+    auto err = add2int->callSerialize(1, 2, to_server);
+    if( err ) { throw MyException() };
+    auto result = add2int->decryptReturned(from_server);
+    assert(result == 3);
+}