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-cli/integrationtest/test/util.ts

@@ -6,23 +6,19 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {AppModuleFactory, AppModuleRef, bootstrapModuleFactory} from '@angular/core';
+import {NgModuleFactory, NgModuleRef, bootstrapModuleFactory} from '@angular/core';
 import {ComponentFixture} from '@angular/core/testing';
 import {serverPlatform} from '@angular/platform-server';
 
+import {MainModule} from '../src/module';
 import {MainModuleNgFactory} from '../src/module.ngfactory';
 
-export function createModule<M>(factory: AppModuleFactory<M>): AppModuleRef<M> {
-  return bootstrapModuleFactory(factory, serverPlatform());
+export function createModule(): NgModuleRef<MainModule> {
+  return bootstrapModuleFactory(MainModuleNgFactory, serverPlatform());
 }
 
-export function createComponent<C>(
-    comp: {new (...args: any[]): C},
-    moduleFactory: AppModuleFactory<any> = null): ComponentFixture<C> {
-  if (!moduleFactory) {
-    moduleFactory = MainModuleNgFactory;
-  }
-  const moduleRef = createModule(moduleFactory);
+export function createComponent<C>(comp: {new (...args: any[]): C}): ComponentFixture<C> {
+  const moduleRef = createModule();
   const compRef =
       moduleRef.componentFactoryResolver.resolveComponentFactory(comp).create(moduleRef.injector);
   return new ComponentFixture(compRef, null, null);