Program > Portfolio category + related categories (#2339)

* add is_taxonomy to blog and agenda categories + set portfolio program categories

* program related_categories

* fix tests

* category slug with ancestors

* harmonize taxonomies

* add as localized tree to program category l10ns

* harmonisation !

* is_taxonomy

* wip is_taxonomy in person and orga categories

* static categories in orga and people

* fix permalink and git path + hugo_slug

* fix

* static versions

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Co-authored-by: Arnaud Levy <arnaud.levy@noesya.coop>
Co-authored-by: Arnaud Levy <contact@arnaudlevy.com>