Added quick filters in metadata

Author: mairaw

api/index.md

@@ -2,6 +2,9 @@
 layout: ApiBrowserPage
 hide_bc: true
 title: .NET API Browser
+quickFilterColumn1: netframework-4.7,netcore-2.0,netstandard-2.0
+quickFilterColumn2: xamarinios-10.8,xamarinandroid-7.1,xamarinmac-3.0
+quickFilterColumn3: azuremgmtresourcemanager-1.5.0-preview,appinsights-2.3.0-beta3,aspnetcore-2.0
 ---
 
 # .NET API Browser