Merge pull request #197 from noesya/v5.1-block-class-utils

layouts/partials/GetBlockClass

layouts/partials/blocks/templates/agenda.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

layouts/partials/blocks/templates/features.html

layouts/partials/blocks/templates/files.html

layouts/partials/blocks/templates/gallery.html

layouts/partials/blocks/templates/image.html

layouts/partials/blocks/templates/key_figures.html

layouts/partials/blocks/templates/license.html

layouts/partials/blocks/templates/organizations.html

layouts/partials/blocks/templates/pages.html

layouts/partials/blocks/templates/persons.html

layouts/partials/blocks/templates/posts.html

layouts/partials/blocks/templates/programs.html

layouts/partials/blocks/templates/sound.html