refactor: remove obsolete period archives template

templates/period_archives.html

@@ -1,14 +0,0 @@
-{% extends "base.html" %}
-
-{% block title %}{{ SITENAME|striptags }} - {{ period | reverse | join(' ') }} archives{% endblock %}
-
-{% block content %}
-    <h2>Archives for {{ period | reverse | join(' ') }}</h2>
-
-    <dl>
-        {% for article in dates %}
-            <dt>{{ article.locale_date }}</dt>
-            <dd><a href="{{ SITEURL }}/{{ article.url }}">{{ article.title }}</a></dd>
-        {% endfor %}
-    </dl>
-{% endblock %}