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/ng_module_resolver_mock.ts

@@ -0,0 +1,46 @@
+/**
+ * @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
+ */
+
+import {Compiler, Injectable, Injector, NgModuleMetadata, Type} from '@angular/core';
+
+import {NgModuleResolver} from '../index';
+import {Map} from '../src/facade/collection';
+
+@Injectable()
+export class MockNgModuleResolver extends NgModuleResolver {
+  /** @internal */
+  _ngModules = new Map<Type, NgModuleMetadata>();
+
+  constructor(private _injector: Injector) { super(); }
+
+  private get _compiler(): Compiler { return this._injector.get(Compiler); }
+
+  private _clearCacheFor(component: Type) { this._compiler.clearCacheFor(component); }
+
+  /**
+   * Overrides the {@link NgModuleMetadata} for a module.
+   */
+  setNgModule(type: Type, metadata: NgModuleMetadata): void {
+    this._ngModules.set(type, metadata);
+    this._clearCacheFor(type);
+  }
+
+  /**
+   * Returns the {@link NgModuleMetadata} for a module:
+   * - Set the {@link NgModuleMetadata} to the overridden view when it exists or fallback to the
+   * default
+   * `NgModuleResolver`, see `setNgModule`.
+   */
+  resolve(type: Type, throwIfNotFound = true): NgModuleMetadata {
+    var metadata = this._ngModules.get(type);
+    if (!metadata) {
+      metadata = super.resolve(type, throwIfNotFound);
+    }
+    return metadata;
+  }
+}