Make template usage on dashboard easier to scan

The dashboard looked a bit table-y. This commit makes four main changes:

- show a bar chart (drawn in CSS) for template usage (only shown if
  you’ve used more than one template recently)
- only break down template usage by template name, not template type
  (because that’s happening with the big numbers)
- change the style of the ‘show more’ links under each section so that
  they are all consistent, and a little less busy (one less keyline)
- remove the ‘recent templates‘ title so that the first two sections of
  the page group under ‘in the last 7 days’

app/templates/views/dashboard/all-template-statistics.html

@@ -5,13 +5,16 @@
 {% endblock %}
 
 {% block maincolumn_content %}
-  <h1 class='heading-large'>
-  	Templates sent this year
-  </h1>
-  <p>
-	1 April 2016 to date
-  </p>
-  {% with period = "" %}
-	  {% include 'views/dashboard/template-statistics.html' %}
-  {% endwith %}
+
+  <div class="grid-row bottom-gutter">
+    <div class="column-half">
+      <h2 class="heading-large">Templates sent</h2>
+    </div>
+    <div class="column-half">
+      <span class="align-with-heading-copy">1 April 2016 to date</span>
+    </div>
+  </div>
+
+  {% include 'views/dashboard/template-statistics.html' %}
+
 {% endblock %}