Remove raw markdown output

I don't think it's ever been that useful. It was originally implemented
as kind of a test of what Hugo output formats were capable of. It waited
for the `ugly` option to get added in `outputFormats` and the novelty of
a new Hugo feature was part of the fun of it.

As mentioned in 7a65f92f53:

    I believe I originally added it because I thought it was somewhat
    hard to get from the "View history" commit list to the actual page
    but I feel like people who care enough to go looking for the source
    code will be willing to use GitHub to find the actual source file.

layouts/_partials/page-metadata/item/viewraw.html

@@ -1,8 +0,0 @@
-{{ with .OutputFormats.Get "markdown" }}
-    <span class="page-metadata-item post-meta-view-markdown" aria-label="{{ i18n "aria_post_meta_view_markdown" }}">
-        {{ partial "icon.html" "code" }}
-        <a href="{{ .Permalink }}" target="_blank">
-            {{- i18n "view_markdown" -}}
-        </a>
-    </span>
-{{ end }}

layouts/_partials/page-metadata/post-full.html

@@ -20,7 +20,6 @@
         {{ partial "page-metadata/item/authors.html" . }}
         {{ partial "page-metadata/item/readingtime.html" . }}
         {{ partial "page-metadata/item/edithistory.html" . }}
-        {{ partial "page-metadata/item/viewraw.html" . }}
         {{ partial "page-metadata/item/comments-counter.html" . }}
 
         {{ partial "page-metadata/item/categories.html" . }}

layouts/page.markdown.md

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