p2pool: export data to an external web-server

Dumps data to JSON files which can be later served by a web-server.

src/params.h

@@ -36,6 +36,7 @@ struct Params
 	std::string m_p2pAddresses{ "[::]:37890,0.0.0.0:37890" };
 	std::string m_p2pPeerList;
 	std::string m_config;
+	std::string m_apiPath;
 };
 
 } // namespace p2pool