[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-pistache/impl/PetApiImpl.h

@@ -0,0 +1,64 @@
+/**
+* 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 (https://openapi-generator.tech).
+* https://openapi-generator.tech
+* Do not edit the class manually.
+*/
+
+/*
+* PetApiImpl.h
+*
+* 
+*/
+
+#ifndef PET_API_IMPL_H_
+#define PET_API_IMPL_H_
+
+
+#include <pistache/endpoint.h>
+#include <pistache/http.h>
+#include <pistache/router.h>
+#include <memory>
+
+#include <PetApi.h>
+
+#include "ApiResponse.h"
+#include "Pet.h"
+#include <string>
+
+namespace org {
+namespace openapitools {
+namespace server {
+namespace api {
+
+using namespace org::openapitools::server::model;
+
+class PetApiImpl : public org::openapitools::server::api::PetApi {
+public:
+    PetApiImpl(Pistache::Address addr);
+    ~PetApiImpl() { };
+
+    void add_pet(const std::shared_ptr<Pet> &pet, Pistache::Http::ResponseWriter &response);
+    void delete_pet(const int64_t &petId, const Optional<Net::Http::Header::Raw> &apiKey, Pistache::Http::ResponseWriter &response);
+    void find_pets_by_status(const Optional<std::string> &status, Pistache::Http::ResponseWriter &response);
+    void find_pets_by_tags(const Optional<std::string> &tags, Pistache::Http::ResponseWriter &response);
+    void get_pet_by_id(const int64_t &petId, Pistache::Http::ResponseWriter &response);
+    void update_pet(const std::shared_ptr<Pet> &pet, Pistache::Http::ResponseWriter &response);
+    void update_pet_with_form(const Pistache::Rest::Request &request, Pistache::Http::ResponseWriter &response);
+    void upload_file(const Pistache::Rest::Request &request, Pistache::Http::ResponseWriter &response);
+
+};
+
+}
+}
+}
+}
+
+
+
+#endif