feat(forms): add modules for forms and deprecatedForms (#9859)

Closes #9732

BREAKING CHANGE:

We have removed the deprecated form directives from the built-in platform directive list, so apps are not required to package forms with their app. This also makes forms friendly to offline compilation.

Instead, we have exposed three modules:

OLD API:
- `DeprecatedFormsModule`

NEW API:
- `FormsModule`
- `ReactiveFormsModule`

If you provide one of these modules, the default forms directives and providers from that module will be available to you app-wide.  Note: You can provide both the `FormsModule` and the `ReactiveFormsModule` together if you like, but they are fully-functional separately.

**Before:**
```ts
import {disableDeprecatedForms, provideForms} from @angular/forms;

bootstrap(App, [
   disableDeprecatedForms(),
   provideForms()
]);
```

**After:**

```ts
import {DeprecatedFormsModule} from @angular/common;

bootstrap(App, {modules: [DeprecatedFormsModule] });
```

-OR-

```ts
import {FormsModule} from @angular/forms;

bootstrap(App, {modules: [FormsModule] });
```

-OR-

```ts
import {ReactiveFormsModule} from @angular/forms;

bootstrap(App, {modules: [ReactiveFormsModule] });
```

You can also choose not to provide any forms module and run your app without forms.

Or you can choose not to provide any forms module *and* provide form directives at will.  This will allow you to use the deprecatedForms API for some components and not others.

```
import {FORM_DIRECTIVES, FORM_PROVIDERS} from @angular/forms;

@Component({
   selector: some-comp,
   directives: [FORM_DIRECTIVES],
   providers: [FORM_PROVIDERS]
})
class SomeComp
```

modules/@angular/common/test/forms-deprecated/integration_spec.ts

@@ -7,11 +7,11 @@
  */
 
 import {NgFor, NgIf} from '@angular/common';
-import {Control, ControlGroup, ControlValueAccessor, FORM_DIRECTIVES, FORM_PROVIDERS, NG_ASYNC_VALIDATORS, NG_VALIDATORS, NgControl, NgForm, RadioButtonState, Validator, Validators} from '@angular/common/src/forms-deprecated';
+import {Control, ControlGroup, ControlValueAccessor, DeprecatedFormsModule, NG_ASYNC_VALIDATORS, NG_VALIDATORS, NgControl, NgForm, RadioButtonState, Validator, Validators} from '@angular/common/src/forms-deprecated';
 import {TestComponentBuilder} from '@angular/compiler/testing';
 import {Component, Directive, EventEmitter, Output} from '@angular/core';
 import {Input, Provider, forwardRef} from '@angular/core';
-import {ComponentFixture, fakeAsync, flushMicrotasks, tick} from '@angular/core/testing';
+import {ComponentFixture, configureModule, fakeAsync, flushMicrotasks, tick} from '@angular/core/testing';
 import {afterEach, beforeEach, ddescribe, describe, expect, iit, inject, it, xit} from '@angular/core/testing/testing_internal';
 import {AsyncTestCompleter} from '@angular/core/testing/testing_internal';
 import {By} from '@angular/platform-browser/src/dom/debug/by';
@@ -25,6 +25,8 @@ import {PromiseWrapper} from '../../src/facade/promise';
 export function main() {
   describe('integration tests', () => {
 
+    beforeEach(() => {configureModule({modules: [DeprecatedFormsModule]})});
+
     it('should initialize DOM elements with the given form object',
        inject(
            [TestComponentBuilder, AsyncTestCompleter],
@@ -1548,10 +1550,7 @@ class UniqLoginValidator implements Validator {
 @Component({
   selector: 'my-comp',
   template: '',
-  directives: [
-    FORM_DIRECTIVES, WrappedValue, MyInput, NgIf, NgFor, LoginIsEmptyValidator, UniqLoginValidator
-  ],
-  providers: [FORM_PROVIDERS]
+  directives: [WrappedValue, MyInput, NgIf, NgFor, LoginIsEmptyValidator, UniqLoginValidator]
 })
 class MyComp8 {
   form: any;