ADMIN CLI: support grant/revoke user admin authorization

[JinHai-CN]

What problem does this PR solve?

admin> grant admin 'aaa@aaa1.com';
Fail to grant aaa@aaa1.com admin authorization, code: 404, message: User 'aaa@aaa1.com' not found
admin> grant admin 'aaa@aaa.com';
Grant successfully!
admin> revoke admin 'aaa1@aaa.com';
Fail to revoke aaa1@aaa.com admin authorization, code: 404, message: User 'aaa1@aaa.com' not found
admin> revoke admin 'aaa@aaa.com';
Revoke successfully!
admin> revoke admin 'aaa@aaa.com';
aaa@aaa.com isn't superuser, yet!
admin> grant admin 'aaa@aaa.com';
Grant successfully!
admin> grant admin 'aaa@aaa.com';
aaa@aaa.com is already superuser!
admin> revoke admin 'aaa@aaa.com';
Revoke successfully!

Type of change

• New Feature (non-breaking change which adds functionality)