convert files enconding recursively

https://stackoverflow.com/questions/44980220/convert-files-enconding-recursively

The RecursiveIteratorIterator class
https://www.php.net/manual/en/class.recursiveiteratoriterator.php
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Saving multiple files in a folder as UTF-8 encoded using PowerShell
https://cyanbyfuchsia.wordpress.com/2013/05/15/saving-multiple-files-in-a-folder-as-utf-8-encoded-using-powershell/

Convert text files recursively to UTF-8 in PowerShell

https://superuser.com/questions/397890/convert-text-files-recursively-to-utf-8-in-powershell