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?
{
    auto address = makeSocketAddress(host, port, &logger());
#if !defined(POCO_CLICKHOUSE_PATCH) || POCO_VERSION < 0x01090100
    if (secure)
        
        
        socket.bind(address,  true);
    else
#endif
#if POCO_VERSION < 0x01080000
    socket.bind(address,  true);
#else
    socket.bind(address,  true,  config().getBool("listen_reuse_port", false));
#endif
    socket.listen( config().getUInt("listen_backlog", 64));
    return address;
}
void Keeper::createServer(const std::string & listen_host, const char * port_name, bool listen_try, CreateServerFunc && func) const