document list extensions (demo shell) (#4511)

* doclist extensibility test page

* desktopOnly support

* extensions category, custom column

* update code

* Fix styling for column templates

* update package lock

demo-shell/src/app/app.routes.ts

@@ -223,6 +223,11 @@ export const appRoutes: Routes = [
                 component: FilesComponent,
                 canActivate: [AuthGuardEcm]
             },
+            {
+                path: 'extensions/document-list/presets',
+                canActivate: [AuthGuardEcm],
+                loadChildren: './components/document-list/extension-presets/extension-presets.module#ExtensionPresetsModule'
+            },
             {
                 path: 'files/:id',
                 component: FilesComponent,