Add a logout confirmation

This patch remove the custom rule in router responsible to redirect
logout to index page and place a template with pre-translated strings.

This is part of Aube patchset for Re2o to unify the login procedure with
Django Contrib Auth.

re2o/urls.py

@@ -46,7 +46,6 @@ from __future__ import unicode_literals
 from django.conf import settings
 from django.conf.urls import include, url
 from django.contrib import admin
-from django.contrib.auth import views as auth_views
 from django.views.generic import RedirectView
 
 from .views import index, about_page, contact_page
@@ -58,7 +57,6 @@ urlpatterns = [
     url(r'^$', index, name='index'),
     url(r'^about/$', about_page, name='about'),
     url(r'^contact/$', contact_page, name='contact'),
-    url('^logout/', auth_views.logout, {'next_page': '/'}),
     url('^', include('django.contrib.auth.urls')),
     url(r'^i18n/', include('django.conf.urls.i18n')),
     url(r'^admin/', include(admin.site.urls)),

templates/registration/logged_out.html

@@ -0,0 +1,18 @@
+{% extends "registration/logged_out.html" %}
+{% comment %}
+SPDX-License-Identifier: GPL-2.0-or-later
+
+Copyright © 2019  Alexandre Iooss
+{% endcomment %}
+{% load i18n %}
+
+{% block breadcrumbs %}
+    <div class="breadcrumbs">
+        <a href="{% url 'index' %}">{% trans 'Home' %}</a>
+    </div>
+{% endblock %}
+
+{% block content %}
+    <p>{% trans "Thanks for spending some quality time with the Web site today." %}</p>
+    <p><a href="{% url 'index' %}">{% trans 'Log in again' %}</a></p>
+{% endblock %}