Resolve "Provide base templates for e-mails generated by apps"

Closes #439 (closed)

aleksis/core/templates/templated_email/base.email

+{% load i18n html2text %}
+
+{% block subject %}
+ {{ request.site.preferences.general__title": " }}
+{% endblock %}
+
+
+{% block plain %}
+  {% trans "Hello, " %}
+
+
+
+  {% trans "- "{{ request.site.preferences.general__title }} %}
+
+{% endblock %}
+
+{% block html %}
+  <style>
+    {% include "email.css" %}
+  </style>
+  <main>
+    <div class="align-center">
+      <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="green" width="70px" height="70px">
+        <path d="M0 0h24v24H0z" fill="none"/>
+        <path
+            d="M12 2C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm-2 15l-5-5 1.41-1.41L10 14.17l7.59-7.59L19 8l-9 9z"/>
+      </svg>
+    </div>
+
+    <p>{% trans "Hello," %}</p>
+
+    <p>{% trans "- " {{ request.site.preferences.general__title }}%}</p>
+  </main>
+{% endblock %}