[EPIC] The support of the user system

[qqqttt123]

Describe the proposal

For Gravitino, we will support to manage the privilleges. The basic of privileges is the user system.

Task list

• Polish the document of design doc
• Use the real user to record the audit information
  [Subtask] Use real user for audit information #1206
• Use the real user to execute operations
  [Improvement] Cannot specify Hadoop username for catalog operation #596
• Propose a proper interface of user system
• The support of Ranger
• The support of IAM
• The support of Gravitino internal privileges system
• The support of JDBC
• The support of Hive
• The storage of user information
• The api of user management

[qqqttt123]

This issue if out of date, I will create an new issue to track other things.