Create platform-stats blueprint

Created a platform-stats blueprint and moved the new platform stats
endpoint to the new blueprint (it was previously in the service
blueprint). Since the original platform stats route and the new platform
stats route are now in different blueprints, their view functions can
have the same name without any issues.

tests/app/platform_stats/test_rest.py

@@ -0,0 +1,25 @@
+from datetime import date, datetime
+
+from freezegun import freeze_time
+
+
+@freeze_time('2018-06-01')
+def test_get_new_platform_stats_uses_todays_date_if_no_start_or_end_date_is_provided(admin_request, mocker):
+    today = datetime.now().date()
+    dao_mock = mocker.patch('app.platform_stats.rest.fetch_aggregate_stats_by_date_range_for_all_services')
+    mocker.patch('app.service.rest.statistics.format_statistics')
+
+    admin_request.get('platform_stats.get_new_platform_stats')
+
+    dao_mock.assert_called_once_with(start_date=today, end_date=today)
+
+
+def test_get_new_platform_stats_can_filter_by_date(admin_request, mocker):
+    start_date = date(2017, 1, 1)
+    end_date = date(2018, 1, 1)
+    dao_mock = mocker.patch('app.platform_stats.rest.fetch_aggregate_stats_by_date_range_for_all_services')
+    mocker.patch('app.service.rest.statistics.format_statistics')
+
+    admin_request.get('platform_stats.get_new_platform_stats', start_date=start_date, end_date=end_date)
+
+    dao_mock.assert_called_once_with(start_date=start_date, end_date=end_date)