Alignement et standardisation des options des blocs (#493)

assets/sass/_theme/blocks/posts.sass

assets/sass/_theme/sections/posts.sass

config.yaml

layouts/partials/blocks/templates/agenda.html

layouts/partials/blocks/templates/organizations.html

layouts/partials/blocks/templates/pages.html

layouts/partials/blocks/templates/pages/alternate.html

layouts/partials/blocks/templates/pages/cards.html

layouts/partials/blocks/templates/pages/grid.html

layouts/partials/blocks/templates/pages/large.html

layouts/partials/blocks/templates/pages/list.html

layouts/partials/blocks/templates/persons.html

layouts/partials/blocks/templates/posts.html

layouts/partials/blocks/templates/posts/alternate.html

layouts/partials/blocks/templates/posts/highlight.html

layouts/partials/blocks/templates/posts/large.html

layouts/partials/contents/backlinks.html

layouts/partials/events/event.html

layouts/partials/events/events.html

layouts/partials/pages/children.html