[FIX] website_rating: correctly take into account rating ratio in frontend

PURPOSE

Fix frontend rating and clean a bit module organization

SPECIFICATIONS

Currently when updating a review on slides, the rating value is divided
by 2 on each update as the rating ratio is not taken into account. In this
commit we correctly update the hidden input value during the start function
using the rating ratio.

LINKS

Task 2057301
PR #35870