Purpose
=======
Improve frontend onboarding: add placeholders, improve tour, improve experience
when buying course (display what has been bought, avoid displaying buy now on
an already purchased course).
Specifications
==============
The tour of the front-end has been updated. It adds a step to enter fullscreen
mode and allow users to test it.
It updates the placeholders for the quiz creation, adding examples and hints
to ease user filling fields.
The course purchasing flow has been improved. It adds a direct link to the
purchased course(s) when the payment is done with the `sale_purchased_course`
template.
It also blocks the possibility to rebuy a course if the user is already a
member of said course by showing the buying options only if `channel.is_member`
is False. INdeed it makes no sense to display the "Buy" button when having
already bought the course.
This commit also removes the autocompletion of fields in modals.
Task-2623471
closesodoo/odoo#77050
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>