[IMP] website_slides: add a new kanban view for contents (slide.slide)

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 a kanban view for slide.slide model

  * See https://drive.google.com/a/odoo.com/file/d/1WKj13-C_UCOwh4dN-FRmU9Pp6BsZ_HvT/view?usp=drivesdk

LINKS

Task 1978729
PR #35061