Add new platform admin page

Added a new platform admin page, at '/plaform-admin-new' which shows
different data. This no longer offers the option to filter by test-key,
only by date, and also gives a more detailed break-down of the
notifications and failures sent with a normal / research key.

The existing platform admin stats page ('/platform-admin') has not been
deleted yet so that both pages can be compared.

app/templates/views/platform-admin/index_new.html

@@ -0,0 +1,59 @@
+{% extends "views/platform-admin/_base_template.html" %}
+{% from "components/textbox.html" import textbox %}
+{% from "components/big-number.html" import big_number_simple %}
+{% from "components/message-count-label.html" import message_count_label %}
+{% from "components/status-box.html" import status_box %}
+
+{% block per_page_title %}
+  Platform admin
+{% endblock %}
+
+{% block platform_admin_content %}
+
+  <h1 class="heading-large">
+    Summary
+  </h1>
+
+  <details>
+    <summary>Apply filters</summary>
+    <form autocomplete="off" method="get">
+      {{ textbox(form.start_date, hint="Enter start date in format YYYY-MM-DD") }}
+      {{ textbox(form.end_date, hint="Enter end date in format YYYY-MM-DD") }}
+      </br>
+      <button type="submit" class="button">Filter</button>
+    </form>
+  </details>
+
+  <div class="grid-row bottom-gutter">
+    {% for noti_type in global_stats %}
+      <div class="column-third">
+        {{ big_number_simple(
+            noti_type.black_box.number,
+            message_count_label(noti_type.black_box.number, noti_type.black_box.notification_type)
+          ) }}
+
+        {% for item in noti_type.other_data %}
+          {{ status_box(
+              number=item.number,
+              label=item.label,
+              failing=item.failing,
+              percentage=item.percentage,
+              url=item.url)
+          }}
+        {% endfor %}
+      </div>
+    {% endfor %}
+  </div>
+
+  <div class="grid-row bottom-gutter">
+    {% for noti_type in global_stats %}
+      <div class="column-third">
+        <div class="bordered-text-box">
+          <span class="big-number-number">{{ "{:,}".format(noti_type.test_data.number) }}</span>
+          {{ noti_type.test_data.label }}
+        </div>
+      </div>
+    {% endfor %}
+  </div>
+
+{% endblock %}