* IAM: add support for advanced IAM config file to server command
* Add support for advanced IAM config file in S3 options
* Fix S3 IAM config handling to simplify checks for configuration presence
* simplify
* simplify again
* copy the value
* const
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Co-authored-by: chrislu <chris.lu@gmail.com>
Co-authored-by: Chris Lu <chrislusf@users.noreply.github.com>