add description to category

...lers/admin/communication/website/categories_controller.rb

app/models/communication/website/category.rb

app/models/communication/website/page.rb

app/models/communication/website/post.rb

...ews/admin/communication/website/categories/_form.html.erb

...iews/admin/communication/website/categories/show.html.erb

...ws/admin/communication/website/categories/static.html.erb

config/locales/communication/en.yml

config/locales/communication/fr.yml

db/migrate/20220404140813_add_description_to_category.rb

db/schema.rb

test/fixtures/communication/website/posts.yml