Documentation de l'API avec Swagger et rswag (#2157)

* wip

* temporary fix for rack 3

* wip

* doc

* clean

* auth

* api

* wip

* Update app/controllers/api/osuny/communication/websites/posts_controller.rb

* Update app/controllers/api/osuny/communication/websites/posts_controller.rb

* Update config/initializers/rswag_ui.rb

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