[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/Pet.cpp

@@ -0,0 +1,117 @@
+/**
+ * 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 "Pet.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 {
+
+Pet::Pet()
+{
+    m_Id = 0L;
+    m_Name = "";
+    m_Status = "";
+    
+}
+
+Pet::~Pet()
+{
+}
+
+std::string Pet::toJsonString()
+{
+	std::stringstream ss;
+	ptree pt;
+	pt.put("Id", m_Id);
+	pt.put("Name", m_Name);
+	pt.put("Status", m_Status);
+	write_json(ss, pt, false);
+	return ss.str();
+}
+
+void Pet::fromJsonString(std::string const& jsonString)
+{
+	std::stringstream ss(jsonString);
+	ptree pt;
+	read_json(ss,pt);
+	m_Id = pt.get("Id", 0L);
+	m_Name = pt.get("Name", "");
+	m_Status = pt.get("Status", "");
+}
+
+int64_t Pet::getId() const
+{
+    return m_Id;
+}
+void Pet::setId(int64_t value)
+{
+    m_Id = value;
+}
+std::shared_ptr<Category> Pet::getCategory() const
+{
+    return m_Category;
+}
+void Pet::setCategory(std::shared_ptr<Category> value)
+{
+    m_Category = value;
+}
+std::string Pet::getName() const
+{
+    return m_Name;
+}
+void Pet::setName(std::string value)
+{
+    m_Name = value;
+}
+std::vector<std::string> Pet::getPhotoUrls() const
+{
+    return m_PhotoUrls;
+}
+void Pet::setPhotoUrls(std::vector<std::string> value)
+{
+    m_PhotoUrls = value;
+}
+std::vector<std::shared_ptr<Tag>> Pet::getTags() const
+{
+    return m_Tags;
+}
+void Pet::setTags(std::vector<std::shared_ptr<Tag>> value)
+{
+    m_Tags = value;
+}
+std::string Pet::getStatus() const
+{
+    return m_Status;
+}
+void Pet::setStatus(std::string value)
+{
+    m_Status = value;
+}
+
+}
+}
+}
+}
+