Include front matter in home and list pages if provided

Contents in `_index.md` files will be used if the relevant files
exist, per hugo documentation:
https://gohugo.io/templates/lists/#add-content-and-front-matter-to-list-pages

layouts/index.html

@@ -5,6 +5,8 @@
 	<div class="container wrapper">
 		{{ partial "head.html" . }}
 
+		{{ with .Content }}{{ . }}{{ end }}
+
 		<div class="recent-posts section">
 			<h2 class="section-header">
 				Recent posts