Add posts page; fix post templates

templates/blog.html

@@ -10,17 +10,4 @@ $wrap{"root"}
   </p>
 </section>
 
-<article>
-  <header>
-    <div>
-      <h2>$(title or id)</h2>
-      <time>$(post.publish_date)</time>
-    </div>
-  </header>
-
-  $body
-
-  <div class="mt-16">
-    <a href="/posts">Back to posts</a>
-  </div>
-</article>
+$body