[IMP] website_slides: add a new kanban view for ratings

PURPOSE

eLearning should have its own application in manager. Indeed this is becoming
a big application and having it embedded inside Website application is not
enough anymore. It should also hold updated and easy-to-use menus,
navigation, actions and views in backend.

SPECIFICATIONS

Add in menu Courses, a new entry Reviews
  * Kanban view, full width, no default group by
    * Order by date (most recent on top)
    * See: https://drive.google.com/a/odoo.com/file/d/1IYE1QBIJa26BLugRiafyBop-srkYwndC/view?usp=drivesdk
    * add a tag for unpublished comments
    * Add the pic of the user above the stars
    * Click on card, send to front-end and able to (un)publish the comment
    * Kind of what's on the front-end:  https://drive.google.com/a/odoo.com/file/d/1e9aQSWvUM2QOynRT08XSUzIjFiGnjsv8/view?usp=drivesdk

LINKS

Task 1978729
PR #35061