* migrate examples to openApi part 20: TUTORIAL.md

* various tweaks

* Update doc/TUTORIAL.md

Co-authored-by: Pierre-Yves Bigourdan <10694593+PyvesB@users.noreply.github.com>

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Co-authored-by: Pierre-Yves Bigourdan <10694593+PyvesB@users.noreply.github.com>