fix(router): do not finish bootstrap until all the routes are resolved (#14762)

DEPRECATION:

Use `RouterModule.forRoot(routes, {initialNavigation: 'enabled'})` instead of
`RouterModule.forRoot(routes, {initialNavigtaion: true})`.

Before doing this, move the initialization logic affecting the router
from the bootstrapped component to the boostrapped module.

Similarly, use `RouterModule.forRoot(routes, {initialNavigation: 'disabled'})`
instead of `RouterModule.forRoot(routes, {initialNavigation: false})`.

Deprecated options: 'legacy_enabled', `true` (same as 'legacy_enabled'),
'legacy_disabled', `false` (same as 'legacy_disabled').

The "Router Initial Navigation" design document covers this change.
Read more here:
https://docs.google.com/document/d/1Hlw1fPaVs-PCj5KPeJRKhrQGAvFOxdvTlwAcnZosu5A/edit?usp=sharing

tools/public_api_guard/common/typings/common.d.ts

@@ -94,6 +94,9 @@ export declare class Location {
     static stripTrailingSlash(url: string): string;
 }
 
+/** @experimental */
+export declare const LOCATION_INITIALIZED: InjectionToken<Promise<any>>;
+
 /** @experimental */
 export interface LocationChangeEvent {
     type: string;

tools/public_api_guard/platform-webworker/typings/platform-webworker.d.ts

@@ -93,6 +93,10 @@ export declare const WORKER_APP_LOCATION_PROVIDERS: ({
     useFactory: (platformLocation: WebWorkerPlatformLocation, zone: NgZone) => () => Promise<boolean>;
     multi: boolean;
     deps: (typeof NgZone | typeof PlatformLocation)[];
+} | {
+    provide: InjectionToken<Promise<any>>;
+    useFactory: (platformLocation: WebWorkerPlatformLocation) => Promise<any>;
+    deps: typeof PlatformLocation[];
 })[];
 
 /** @experimental */

tools/public_api_guard/router/typings/router.d.ts

@@ -76,7 +76,7 @@ export declare type Event = NavigationStart | NavigationEnd | NavigationCancel |
 export interface ExtraOptions {
     enableTracing?: boolean;
     errorHandler?: ErrorHandler;
-    initialNavigation?: boolean;
+    initialNavigation?: InitialNavigation;
     preloadingStrategy?: any;
     useHash?: boolean;
 }