[REF] website, *: remove hardcoded image urls

* = website_forum, website_profile, website_sale,
website_sale_comparison, website_slides, website_slides_survey

Some image links were hard coded in the xml views of website, now they
are replaced with website.image_url(model, field).

Part of https://github.com/odoo/odoo/pull/34149


task-2007400

closes odoo/odoo#34149

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>