UX was lacking comparing to other payment providers,
important fields were not always shown or were checkboxes
when they should be automatically true.
In order to make payment flow easier and more intitive, unnecessary fields
were removed, email is automatically filled. Now when user cancels transaction
on paypal before paying, it automatically cancels transaction on Odoo. Additionaly, quick
onboarding is only available if user already has paypal account and Stripe
no longer installs ond configures paypal if Stripe's onboarding get canceled.
task-2854184
closesodoo/odoo#104974
Related: odoo/upgrade#4025
Related: odoo/documentation#3063
Signed-off-by: Antoine Vandevenne (anv) <anv@odoo.com>