add stats boxes to platform admin page

moved a couple of stats summary functions from dashboard to a shared statistics_utils file

app/statistics_utils.py

@@ -0,0 +1,50 @@
+from datetime import datetime
+from dateutil import parser
+from functools import reduce
+
+
+def sum_of_statistics(delivery_statistics):
+
+    statistics_keys = (
+        'emails_delivered',
+        'emails_requested',
+        'emails_failed',
+        'sms_requested',
+        'sms_delivered',
+        'sms_failed'
+    )
+
+    if not delivery_statistics or not delivery_statistics[0]:
+        return {
+            key: 0 for key in statistics_keys
+        }
+
+    return reduce(
+        lambda x, y: {
+            key: x.get(key, 0) + y.get(key, 0)
+            for key in statistics_keys
+        },
+        delivery_statistics
+    )
+
+
+def add_rates_to(delivery_statistics):
+
+    return dict(
+        emails_failure_rate=(
+            "{0:.1f}".format(
+                float(delivery_statistics['emails_failed']) / delivery_statistics['emails_requested'] * 100
+            )
+            if delivery_statistics['emails_requested'] else 0
+        ),
+        sms_failure_rate=(
+            "{0:.1f}".format(
+                float(delivery_statistics['sms_failed']) / delivery_statistics['sms_requested'] * 100
+            )
+            if delivery_statistics['sms_requested'] else 0
+        ),
+        week_end_datetime=parser.parse(
+            delivery_statistics.get('week_end', str(datetime.utcnow()))
+        ),
+        **delivery_statistics
+    )