fix(ivy): platform module bootstrap does not resolve resources (#29083)

Currently with ViewEngine, if someone runs the platform's
`bootstrapModule` method in order to boostrap a module in
JIT mode, external component resources are properly resolved
*automatically*.

Currently with Ivy, the developer would need to manually call
`resolveComponentResources` in order to asynchronously fetch
the determined external component resources. In order to make
this backwards compatible with ViewEngine, and also since
platforms can already specify a `ResourceLoader` compiler
provider, we need to automatically resolve all external
component resources on module bootstrap.

--

Since the `ResourceLoader` is part of the `@angular/compiler`,
because ViewEngine performed the factory creation in the compiler,
we can't access the `ResourceLoader` token from within core.

In order to workaround this without introducing a breaking change,
we just proxy the `ResourceLoader` token to `core` through the
compiler facade. In the future, we should be able to move the
`ResourceLoader` to core when ViewEngine code no longer exists in
the `@angular/compiler`.

PR Close #29083

packages/core/src/compiler/compiler_facade_interface.ts

@@ -41,10 +41,15 @@ export interface CompilerFacade {
   createParseSourceSpan(kind: string, typeName: string, sourceUrl: string): ParseSourceSpan;
 
   R3ResolvedDependencyType: typeof R3ResolvedDependencyType;
+  ResourceLoader: {new (): ResourceLoader};
 }
 
 export interface CoreEnvironment { [name: string]: Function; }
 
+export type ResourceLoader = {
+  get(url: string): Promise<string>| string;
+};
+
 export type StringMap = {
   [key: string]: string;
 };