Create markdown output template

Further progress is blocked by Hugo feature requests:

- https://discourse.gohugo.io/t/render-alternative-output-format-outside-of-leaf-bundle-subdirectory/46968
- https://github.com/gohugoio/hugo/issues/8927

exampleSite/hugo.yaml

@@ -15,6 +15,9 @@ taxonomies:
 markup: # this just keeps the bobatheme markup styling
   _merge: deep
 
+outputs:
+  _merge: deep
+
 params:
   author:
     name: bbaovanc

hugo.yaml

@@ -12,6 +12,11 @@ taxonomies:
   author: authors
   series: series
 
+outputs:
+  page:
+    - html
+    - markdown
+
 privacy:
   googleAnalytics:
     disable: true

layouts/_default/single.markdown.md

@@ -0,0 +1,9 @@
+{{ with .File -}}
+  {{ with (.Path | readFile) -}}
+    {{ . -}}
+  {{ else -}}
+    {{ errorf "file not found: %s" .Path -}}
+  {{ end -}}
+{{ else -}}
+  {{ errorf "no file available for markdown template?" -}}
+{{ end -}}