Admin reports with accounts (#2092)

* Add a ReportFilter class

* Add reports and targeted_reports relationships to Account

* Use ReportFilter from admin/reports controller

* Link to admin/reports filtered views from admin account show view

* Add indexes to reports.account_id and reports.target_account_id

app/controllers/admin/reports_controller.rb

@@ -49,14 +49,18 @@ module Admin
     end
 
     def filtered_reports
-      filtering_scope.order('id desc').includes(
+      ReportFilter.new(filter_params).results.order('id desc').includes(
         :account,
         :target_account
       )
     end
 
-    def filtering_scope
-      params[:resolved].present? ? Report.resolved : Report.unresolved
+    def filter_params
+      params.permit(
+        :account_id,
+        :resolved,
+        :target_account_id
+      )
     end
 
     def set_report