add Activity widget

client/coral-admin/src/graphql/fragments/assetMetricsView.graphql

@@ -4,6 +4,7 @@ fragment metrics on Asset {
   url
   author
   created_at
+  commentCount
   action_summaries {
     type: __typename
     actionCount

client/coral-admin/src/graphql/queries/metricsQuery.graphql

@@ -7,4 +7,7 @@ query Metrics ($from: Date!, $to: Date!) {
   assetsByLike: assetMetrics(from: $from, to: $to, sort: LIKE) {
     ...metrics
   }
+  assetsByActivity: assetMetrics(from: $from, to: $to, sort: ACTIVITY) {
+    ...metrics
+  }
 }