[A11Y] Ajout d'un label visible pour le TA et sans css aux liens externes (#581)

layouts/partials/blocks/templates/links.html

layouts/partials/blocks/templates/organizations.html

layouts/partials/commons/share.html

layouts/partials/locations/map.html

layouts/partials/organizations/contact-details.html

layouts/partials/persons/contact-details.html

layouts/partials/persons/contacts.html

layouts/partials/publications/downloads.html