Revert "remove archive and templates"

This reverts commit 67bdf28216.

templates/page.html

@@ -0,0 +1,10 @@
+{% extends "_default/base.html" %}
+
+{% block content %}
+
+<main>
+    <script src="https://cdn.jsdelivr.net/npm/mermaid/dist/mermaid.min.js"></script>
+    <script>mermaid.initialize({startOnLoad:true});</script>
+    {{page.content | safe}}
+
+ </main> {% endblock content %}