[REF] website_slides: redesign quiz widget

This commit makes the quiz widget a real odoo widget that triggers up some
events. The widget is now only responsible of

 * fetching quiz data (if not given)
 * decorating the anwsers according to the result
 * displaying message (error or modal)

To do so, some code move/rewrite was needed

 * extract and factorize some template
 * add 'sudo' on technical model to avoid access rights error
 * factorize some python method from controller to model
 * remove some CSS classes to lighten the code
 * fixing access model error
 * make quiz widget handle the display of error message
 * give browse record for template rendering, rather than slug
 * cleaning some spaghetti code in Fullscreen widget
 * ...

Commit linked to task ID 1941250 and PR #31584.

Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>