feat: dedicated login page for oauth2 logins

templates/security/login_oauth2.html.twig

@@ -0,0 +1,37 @@
+{# The login page as seen by someone who was sent here by another E&P application (ephub, myep-team)
+   to authorize it. Its job is to explain why they are suddenly on a different website and that they
+   will be sent back, which the standard login page never said.
+
+   The grid is the one from security/login.html.twig, minus its marketing column: that keeps the
+   form column at exactly the width it has on the standard login page. #}
+{% extends 'layout_oauth2.html.twig' %}
+
+{% block content %}
+    <div class="grid grid-cols-1 md:grid-cols-2 gap-8 px-4 lg:px-8 py-8 lg:py-16">
+        <div>
+            <h1 class="text-white uppercase pb-4 mb-8 border-b border-primary-bg/40">
+                {% if client_name %}
+                    Anmelden für<br>{{ client_name }}
+                {% else %}
+                    Login<br>MyE&amp;P
+                {% endif %}
+            </h1>
+
+            <p class="mb-6 text-white">
+                Melde dich mit deinem MyE&amp;P-Konto an. Anschließend wirst du automatisch
+                {% if client_name %}zu {{ client_name }} {% endif %}zurückgeleitet.
+            </p>
+
+            {% include '_partials/_login_form.html.twig' %}
+
+            <div class="flex space-x-2">
+                <a href="{{ path('app_reset_password') }}" class="text-white underline">
+                    Passwort vergessen?
+                </a>
+                <a href="{{ path('app_registration') }}" class="text-white underline">
+                    Jetzt registrieren
+                </a>
+            </div>
+        </div>
+    </div>
+{% endblock %}