fix(packages): use ES modules for primary build (#11120)

modules/@angular/router/src/index.ts

@@ -0,0 +1,21 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+
+export {Data, LoadChildren, LoadChildrenCallback, ResolveData, Route, Routes} from './config';
+export {RouterLink, RouterLinkWithHref} from './directives/router_link';
+export {RouterLinkActive} from './directives/router_link_active';
+export {RouterOutlet} from './directives/router_outlet';
+export {CanActivate, CanActivateChild, CanDeactivate, CanLoad, Resolve} from './interfaces';
+export {Event, NavigationCancel, NavigationEnd, NavigationError, NavigationExtras, NavigationStart, Router, RoutesRecognized} from './router';
+export {ExtraOptions, RouterModule, provideRoutes} from './router_module';
+export {RouterOutletMap} from './router_outlet_map';
+export {ActivatedRoute, ActivatedRouteSnapshot, RouterState, RouterStateSnapshot} from './router_state';
+export {PRIMARY_OUTLET, Params} from './shared';
+export {DefaultUrlSerializer, UrlSegment, UrlSerializer, UrlTree} from './url_tree';
+export * from './private_export'