Merge pull request #77 from noesya/a11y/headings

assets/sass/_theme/_utils.sass

assets/sass/_theme/blocks/base.sass

assets/sass/_theme/blocks/image.sass

assets/sass/_theme/blocks/key_figures.sass

assets/sass/_theme/blocks/pages.sass

assets/sass/_theme/blocks/posts.sass

assets/sass/_theme/blocks/timeline.sass

assets/sass/_theme/design-system/layout.sass

assets/sass/_theme/sections/organizations.sass

assets/sass/_theme/sections/posts.sass

assets/sass/_theme/sections/programs.sass

i18n/en.yml

i18n/fr.yml

layouts/partials/blocks/default_title.html

layouts/partials/blocks/templates/call_to_action.html

layouts/partials/blocks/templates/chapter.html

layouts/partials/blocks/templates/contact.html

layouts/partials/blocks/templates/datatable.html

layouts/partials/blocks/templates/definitions.html

layouts/partials/blocks/templates/embed.html