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/components/big-number.html

@@ -1,14 +1,16 @@
 {% macro big_number(number, label, label_link=None, currency='', smaller=False) %}
   <div class="big-number{% if smaller %}-smaller{% endif %}">
-    {% if number is number %}
-      {% if currency %}
-        {{ "{}{:,.2f}".format(currency, number) }}
+    <div class="big-number-number">
+      {% if number is number %}
+        {% if currency %}
+          {{ "{}{:,.2f}".format(currency, number) }}
+        {% else %}
+          {{ "{}{:,}".format(currency, number) }}
+        {% endif %}
       {% else %}
-        {{ "{}{:,}".format(currency, number) }}
+        {{ number }}
       {% endif %}
-    {% else %}
-      {{ number }}
-    {% endif %}
+    </div>
     {% if label_link %}
       <a class="big-number-label" href="{{ label_link }}">{{ label }}</a>
       <a class="big-number-overlay-link" href="{{ label_link }}" aria-hidden="true"></a>

app/templates/components/show-more.html

@@ -0,0 +1,3 @@
+{% macro show_more(url, label) %}
+  <a href="{{ url }}" class="show-more"><span>{{ label }}</span></a>
+{% endmacro %}