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?
{
#if USE_SSL
                Poco::Net::SecureServerSocket socket;
                auto address = socketBindListen(socket, listen_host, port,  true);
                socket.setReceiveTimeout(settings.receive_timeout);
                socket.setSendTimeout(settings.send_timeout);
                servers->emplace_back(port_name, std::make_unique<Poco::Net::TCPServer>(
                    new TCPHandlerFactory(*this,  true,  false),
                    server_pool,
                    socket,
                    new Poco::Net::TCPServerParams));
                LOG_INFO(log, "Listening for connections with secure native protocol (tcp_secure): {}", 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 = "interserver_http_port";
            createServer(listen_host, port_name, listen_try, [&](UInt16 port)
            {
                Poco::Net::ServerSocket socket;
                auto address = socketBindListen(socket, listen_host, port);
                socket.setReceiveTimeout(settings.http_receive_timeout);
                socket.setSendTimeout(settings.http_send_timeout);
                servers->emplace_back(
                    port_name,
                    std::make_unique<HTTPServer>(
                        context(),