refactor(core): change module semantics

This contains major changes to the compiler, bootstrap of the platforms
and test environment initialization.

Main part of #10043
Closes #10164

BREAKING CHANGE:
- Semantics and name of `@AppModule` (now `@NgModule`) changed quite a bit.
  This is actually not breaking as `@AppModules` were not part of rc.4.
  We will have detailed docs on `@NgModule` separately.
- `coreLoadAndBootstrap` and `coreBootstrap` can't be used any more (without migration support).
  Use `bootstrapModule` / `bootstrapModuleFactory` instead.
- All Components listed in routes have to be part of the `declarations` of an NgModule.
  Either directly on the bootstrap module / lazy loaded module, or in an NgModule imported by them.

modules/@angular/compiler/testing/test_component_builder.ts

@@ -87,14 +87,16 @@ export class OverridingTestComponentBuilder extends TestComponentBuilder {
     return clone;
   }
 
-  createAsync<T>(rootComponentType: ConcreteType<T>): Promise<ComponentFixture<T>> {
+  createAsync<T>(rootComponentType: ConcreteType<T>, ngModule: ConcreteType<any> = null):
+      Promise<ComponentFixture<T>> {
     this._applyMetadataOverrides();
-    return super.createAsync(rootComponentType);
+    return super.createAsync(rootComponentType, ngModule);
   }
 
-  createSync<T>(rootComponentType: ConcreteType<T>): ComponentFixture<T> {
+  createSync<T>(rootComponentType: ConcreteType<T>, ngModule: ConcreteType<any> = null):
+      ComponentFixture<T> {
     this._applyMetadataOverrides();
-    return super.createSync(rootComponentType);
+    return super.createSync(rootComponentType, ngModule);
   }
 
   private _applyMetadataOverrides() {