create /danger/snapshots.html template.

This is just the HTML template. The back-end (I.E. defroute in web.lisp) is not
implemented at the time of this commmit.

templates/danger/snapshots.html

@@ -0,0 +1,23 @@
+{% extends "layouts/default.html" %}
+{% block title %}Nicola Ellis & Ritherdon Archive{% endblock %}
+{% block content %}
+<main class="be-main">
+    <h1 class="be-warning">Snapshots (not Back-ups)</h1>
+    <p class="be-warning">
+        <strong>Warning:</strong> Restoring the website from a snapshot will
+        delete all data added to the website after the Snapshot was taken.
+    </p>
+    <p>
+        Below is a collection of <em>Snapshots</em> taken of the website's data (database,
+        Pages, Archive Entries and Storage Files). You can download them or
+        restore the website from a snapshot.
+    </p>
+    <p>
+        <strong>Note:</strong>
+        These Snapshots are not a back-up. If the server goes down, the
+        Snapshots go with it. I recommend you download the Snapshots at regular
+        intervals and use those as the site's <em>back-ups</em>.
+    </p>
+
+</main>
+{% endblock %}