Refactor page meta (#2641)

* Rename include

* Add grid view test pages

* Rename `.post__meta-sep` and use CSS to add line break

* Improve collection grid archive

* Improve page grid archive

* Enable `grid`

* Don't show date icon if there is no `date` value

* Add blank line at EOF

* Add space

* Wrap date and reading time in named `span` elements

_layouts/single.html

@@ -27,7 +27,7 @@ layout: default
       {% unless page.header.overlay_color or page.header.overlay_image %}
         <header>
           {% if page.title %}<h1 id="page-title" class="page__title" itemprop="headline">{{ page.title | markdownify | remove: "<p>" | remove: "</p>" }}</h1>{% endif %}
-          {% include post__meta.html %}
+          {% include page__meta.html %}
         </header>
       {% endunless %}