[Improvement] Change default `HADOOP_USER_NAME` from `datastrato` to `anonymous`

[yuqi1129]

What would you like to be improved?

The default user passed from API and frontend is anonymous if the user is unknown, however, the user used in HDFS and related test is datastrato(Hive docker image) , so we need to change them into the same value.

How should we improve?

No response

[xunliu]

I think we need to keep HADOOP_USER_NAME is datastrato or other name, but not anonymous.
Because in the real scene, not everyone can access Hadoop at will.