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

test/_pages/page-archive-grid.html

@@ -0,0 +1,16 @@
+---
+layout: archive
+title: "Page Archive"
+permalink: /page-archive-grid/
+entries_layout: grid
+author_profile: false
+---
+
+{% assign entries_layout = page.entries_layout | default: 'list' %}
+<section class="taxonomy__section">
+  <div class="entries-{{ entries_layout }}">
+    {% for post in site.pages %}
+      {% include archive-single.html type=entries_layout %}
+    {% endfor %}
+  </div>
+</section>