Add Microformats (#3052)

* Add rel=me to author profile links

* Add h-card Microformats markup

* Add h-entry microformat markup

* Fix missing anchor tag

* Fix h-entry microformat markup on single template

* Use minimal subset of Microformat elements

* Move dt-published to `page__date.html` and remove dt-updated
* Remove "author" and "summary"

Leaves "url" as a hidden element

* Add page link to h1 tag

The h1 tag now contains the Schema-org `url` itemprop and the
Microformats `url` class in an anchor tag.  The anchor tag is styled to
not look like a link.

* Put author 'u-url' on author__name h3

This also puts the same `{{ author.home | default: '/' | absolute_url }}`
construct on `author__avatar` to remove the Jekyll `author.home`
conditional.

Also addresses SCSS text color error.

_sass/minimal-mistakes/_page.scss

@@ -72,6 +72,11 @@ body {
   margin-top: 0;
   line-height: 1;
 
+  a {
+    color: $text-color;
+    text-decoration: none;
+  }
+
   & + .page__meta {
     margin-top: -0.5em;
   }
@@ -556,4 +561,4 @@ body {
       padding-right: 0;
     }
   }
-}
+}