Limit data to last 7 days

Otherwise the page gets really long. Also matches what we have on our
dashboards by default.

app/main/views/performance.py

@@ -12,7 +12,7 @@ from app.main import main
 @main.route("/performance")
 def performance():
     stats = performance_dashboard_api_client.get_performance_dashboard_stats(
-        start_date=(datetime.utcnow() - timedelta(days=90)).date(),
+        start_date=(datetime.utcnow() - timedelta(days=7)).date(),
         end_date=datetime.utcnow().date(),
     )
     stats['organisations_using_notify'] = sorted(

app/templates/views/performance.html

@@ -77,6 +77,9 @@
         {{ item.letters|format_thousands }}
       {% endcall %}
     {% endcall %}
+    <p class="table-show-more-link">
+      Only showing the last {{ notifications_by_type|length }} days
+    </p>
   </div>
 
   <h2 class="govuk-heading-m">
@@ -107,6 +110,9 @@
         {{ item.percentage_under_10_seconds }}%
       {% endcall %}
     {% endcall %}
+    <p class="table-show-more-link">
+      Only showing the last {{ processing_time|length }} days
+    </p>
   </div>
 
   <h2 class="govuk-heading-m">