Add categories to People imports (#2397)

* harmonize and add example files

* map instead of loop

* adjust

* adjust

* adjust

* rollback schema

* Update config/locales/university/en.yml

Co-authored-by: Sébastien Gaya <sebastien.gaya@gmail.com>

* Update config/locales/university/fr.yml

Co-authored-by: Sébastien Gaya <sebastien.gaya@gmail.com>

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Co-authored-by: Sébastien Gaya <sebastien.gaya@gmail.com>