Write a file `uuid` in server's data directory that contains random UUID, generated at startup if file does not exist.

It will be used for several purposes:
- to anonymously identify server in Sentry (currently Sentry is unusable);
- (possible future usage) to identify server in ensemble.

@tavplubix comments?
createHandlerFactory(*this, async_metrics, "InterserverIOHTTPHandler-factory"),
                        server_pool,
                        socket,
                        http_params));
                LOG_INFO(log, "Listening for replica communication (interserver): http://{}", address.toString());
            });
            port_name = "interserver_https_port";
            createServer(listen_host, port_name, listen_try, [&](UInt16 port)
            {
#if USE_SSL
                Poco::Net::SecureServerSocket socket;
                auto address = socketBindListen(socket, listen_host, port,  true);
                socket.setReceiveTimeout(settings.http_receive_timeout);
                socket.setSendTimeout(settings.http_send_timeout);
                servers->emplace_back(
                    port_name,
                    std::make_unique<HTTPServer>(
                        context(),
                        createHandlerFactory(*this, async_metrics, "InterserverIOHTTPSHandler-factory"),
                        server_pool,
                        socket,
                        http_params));
                LOG_INFO(log, "Listening for secure replica communication (interserver): https://{}", address.toString());
#else
                UNUSED(port);
                throw Exception{"SSL support for TCP protocol is disabled because Poco library was built without NetSSL support.",
                        ErrorCodes::SUPPORT_IS_DISABLED};
#endif
            });
            port_name = "mysql_port";