Added basic membership reports

Provide a basic membership reporting ui at reports/groups-membership-report.
Display the daily collected meetup.com membership data in a daily
aggregated form, grouped by continents and countries.

Change-Id: I895f98458f87cb19a73af59067f7ecf81ee8eb04

themes/openstack_bootstrap/custom-sass/partials/_reports.scss

@@ -0,0 +1,15 @@
+#group-report-summary {
+  th, td {
+    width: 50%;
+  }
+  a {
+    color: #30739C;
+    text-decoration: underline;
+  }
+}
+
+#group-report-continent {
+  th, td {
+    width: 50%;
+  }
+}

themes/openstack_bootstrap/custom-sass/style.scss

@@ -21,6 +21,7 @@
 @import 'partials/profile';
 @import 'partials/event';
 @import 'partials/language';
+@import 'partials/reports';
 
 /* Custom override */