Logout should support post

[JonasKs]

This may be unrelated to the PR, but still related to logging out. @JonasKs should the logout view also support post since Django has been moving in that direction? https://docs.djangoproject.com/en/4.1/topics/auth/default/#django.contrib.auth.views.LogoutView

Originally posted by @tim-schilling in https://github.com/snok/django-auth-adfs/issues/273#issuecomment-1424500659