Enhancements: Allow username to auth and set sample

[d0zingcat]

1. As redis allows us to use username/password to login, only allowing user to enter password to authorize is not enough, we need to allow user to pass username along with password as well.
2. For complex structures like Hset or Zset, redis uses samples to quick estimate the memory usage of the items, sometimes it does not prevail the real memory usage for the whole data structure. We have to pass MEMORY USAGE xxxx SAMPLES 0 or more samples to redis in order to make it evaluate each item's real memory usage.
3. Forgive me for the auto formatting 🤣