[C++ server] Adjust the names (script, sample folder, generator) to lang option (#250)

* Renamce C++ server scripts

* Change output folder

* Rename sample folder: pistache-server -> cpp-pistache

* Rename sample folder: restbed -> cpp-restbed

samples/server/petstore/cpp-restbed/model/ApiResponse.cpp

@@ -0,0 +1,93 @@
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * OpenAPI spec version: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI-Generator 3.0.0-SNAPSHOT.
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+
+#include "ApiResponse.h"
+
+#include <string>
+#include <sstream>
+#include <boost/property_tree/ptree.hpp>
+#include <boost/property_tree/json_parser.hpp>
+
+using boost::property_tree::ptree;
+using boost::property_tree::read_json;
+using boost::property_tree::write_json;
+
+namespace org {
+namespace openapitools {
+namespace server {
+namespace model {
+
+ApiResponse::ApiResponse()
+{
+    m_Code = 0;
+    m_Type = "";
+    m_Message = "";
+    
+}
+
+ApiResponse::~ApiResponse()
+{
+}
+
+std::string ApiResponse::toJsonString()
+{
+	std::stringstream ss;
+	ptree pt;
+	pt.put("Code", m_Code);
+	pt.put("Type", m_Type);
+	pt.put("Message", m_Message);
+	write_json(ss, pt, false);
+	return ss.str();
+}
+
+void ApiResponse::fromJsonString(std::string const& jsonString)
+{
+	std::stringstream ss(jsonString);
+	ptree pt;
+	read_json(ss,pt);
+	m_Code = pt.get("Code", 0);
+	m_Type = pt.get("Type", "");
+	m_Message = pt.get("Message", "");
+}
+
+int32_t ApiResponse::getCode() const
+{
+    return m_Code;
+}
+void ApiResponse::setCode(int32_t value)
+{
+    m_Code = value;
+}
+std::string ApiResponse::getType() const
+{
+    return m_Type;
+}
+void ApiResponse::setType(std::string value)
+{
+    m_Type = value;
+}
+std::string ApiResponse::getMessage() const
+{
+    return m_Message;
+}
+void ApiResponse::setMessage(std::string value)
+{
+    m_Message = value;
+}
+
+}
+}
+}
+}
+