fix and prepare post categories

assets/sass/_theme/sections/events.sass

assets/sass/_theme/sections/posts.sass

i18n/en.yml

i18n/fr.yml

layouts/_default/list.html

layouts/_default/single.html

layouts/categories/term.html

layouts/events_categories/list.html

layouts/events_categories/term.html

layouts/pages/list.html

layouts/partials/blocks/templates/posts.html

layouts/partials/categories/hero-list.html

layouts/partials/categories/hero-term.html

layouts/partials/diplomas/hero-list.html

layouts/partials/events/categories.html

layouts/partials/events/event-infos.html

layouts/partials/events/event.html

layouts/partials/events/events.html

layouts/partials/pages/toc.html

layouts/partials/posts/categories.html