This commit adds new `embed_viewer` widget which will be used display URLs via embedded iframes. You can add any valid URL to display page via iframe, although widget automatically converts raw google slide URL into embedded URL. Task ID: 1909010 closes odoo/odoo#29404 Signed-off-by: Simon Lejeune (sle) <sle@openerp.com> Co-authored-by: pga-odoo <pga@odoo.com>