Update email footers to remove donation request

Author: sthapa

froide/templates/emails/footer.html

@@ -2,7 +2,5 @@
 <p style="font-size:small;-webkit-text-size-adjust:none;color:#444;">
     &mdash;
     <br />
-    {% block content %}
-        {% blocktrans %}Support Froide by <a href="https://okfn.de/spenden/">donating to Open Knowledge Foundation Germany</a>{% endblocktrans %}
-    {% endblock %}
+    <!-- UIPA footer -->
 </p>

froide/templates/emails/footer.txt

@@ -1,4 +1 @@
 {% load i18n %}{% autoescape off %}--
-{% blocktrans %}Support Froide by donating to Open Knowledge Foundation Germany:
-https://okfn.de/spenden/
-{% endblocktrans %}{% endautoescape %}