### What problem does this PR solve?
- Admin client support show user and create user command.
- Admin client support alter user password and active status.
- Admin client support list user datasets.
issue: #10241
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Move base64 related function to api/common/base64.py
### Type of change
- [x] Refactoring
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Signed-off-by: jinhai <haijin.chn@gmail.com>
