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/src/ng_module_resolver.ts

@@ -0,0 +1,39 @@
+/**
+ * @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 {Injectable, NgModuleMetadata} from '@angular/core';
+
+import {ReflectorReader, reflector} from '../core_private';
+import {BaseException} from '../src/facade/exceptions';
+import {Type, isBlank, isPresent, stringify} from '../src/facade/lang';
+
+function _isNgModuleMetadata(obj: any): obj is NgModuleMetadata {
+  return obj instanceof NgModuleMetadata;
+}
+
+/**
+ * Resolves types to {@link NgModuleMetadata}.
+ */
+@Injectable()
+export class NgModuleResolver {
+  constructor(private _reflector: ReflectorReader = reflector) {}
+
+  resolve(type: Type, throwIfNotFound = true): NgModuleMetadata {
+    const ngModuleMeta: NgModuleMetadata =
+        this._reflector.annotations(type).find(_isNgModuleMetadata);
+
+    if (isPresent(ngModuleMeta)) {
+      return ngModuleMeta;
+    } else {
+      if (throwIfNotFound) {
+        throw new BaseException(`No NgModule metadata found for '${stringify(type)}'.`);
+      }
+      return null;
+    }
+  }
+}