Rationalisation des menus (#2702)

app/assets/stylesheets/admin/design-system/nav.sass

app/assets/stylesheets/admin/osuny/search.sass

app/controllers/admin/university/application_controller.rb

app/controllers/admin/users_controller.rb

app/services/osuny/simple_navigation_renderer.rb

app/views/admin/application/components/_nav.html.erb

app/views/admin/application/components/_search.html.erb

app/views/admin/dashboard/namespace.html.erb

config/locales/administration/en.yml

config/locales/administration/fr.yml

config/locales/communication/en.yml

config/locales/communication/fr.yml

config/locales/education/en.yml

config/locales/education/fr.yml

config/locales/en.yml

config/locales/extranet/fr.yml

config/locales/fr.yml

config/locales/research/en.yml

config/locales/research/fr.yml

config/locales/university/en.yml