Bring consistency to templates, update structure to use new base

alchemy/templates/period_archives.html

@@ -0,0 +1,18 @@
+{% extends "base.html" %}
+
+{% block title %}
+Archives for {{ period | reverse | join(' ') }} {{ super() }}
+{% endblock %}
+
+{% block page_header %}
+Archives for {{ period | reverse | join(' ') }}
+{% endblock %}
+
+{% block content %}
+<dl class="dl-horizontal">
+  {% for article in dates %}
+  <dt>{{ article.locale_date }}</dt>
+  <dd><a href="{{ SITEURL }}/{{ article.url }}">{{ article.title }}</a></dd>
+  {% endfor %}
+</dl>
+{% endblock %}