match page.html template styling with archive-entry template (#6).

The page.html template's text was filling the entire width of the browser window
-- regardless of its size. Nic wanted the page entries to match the max-width
size used by the archive-entry template. This change wraps the CSS classes and
HTML tags in the page.html template's content-area with the same ones used in
the archive-entry.html template.

templates/page.html

@@ -55,10 +55,11 @@
     <div id="hits"></div>
 </div>
 
-<main>
-  {{data | safe}}
-</main>
-
+<article class="fe-article">
+    <div class="fe-article-body">
+        {{data | safe}}
+    </div>
+</article>
 
 <script>
  let server = "{{system-data.first.search-url}}";