templates: add blocks for easier reuse of oauth2 templates (#22923)

fargo/templates/fargo/oauth2/authorize.html

@@ -3,6 +3,9 @@
 
 {% block content %}
 <div id="fargo-oauth2-authorize">
+  {% block form-intro %}
+  {% endblock %}
+  {% block form %}
   <form method="post" enctype="multipart/form-data">
     {% csrf_token %}
     {{ form.as_p  }}
@@ -11,5 +14,6 @@
       <button name="cancel">{% trans "Cancel" %}</button>
     </div>
   </form>
+  {% endblock %}
 </div>
 {% endblock %}

fargo/templates/fargo/oauth2/confirm.html

@@ -4,12 +4,17 @@
 {% block content %}
 <div id="fargo-oauth2-confirm">
   {% if error_message %}
+    {% block error-message %}
     <p>{% trans error_message %}</p>
     <a href="{{ redirect_uri }}">{% trans "Continue to your client url" %}</a>
+    {% endblock %}
   {% else %}
+    {% block form-intro %}
       <p>{% blocktrans %}
         Do you accept to add <em class="filename">{{ filename }}</em> to your portfolio?
       {% endblocktrans %}</p>
+    {% endblock %}
+    {% block form %}
     <form id="send-file" method="post" enctype="multipart/form-data">
       {% csrf_token %}
       <div class="buttons">
@@ -17,6 +22,7 @@
         <button name="cancel">{% trans "Cancel" %}</button>
       </div>
     </form>
+    {% endblock %}
   {% endif %}
 </div>
 {% endblock %}