feat(common): rename underlying NgFor class and add a type parameter (#14104)

Note, this affects the underlying class and should not affect usage.

DEPRECATION:
- the `NgFor` class is now deprecated. Use `NgForOf<T>` instead.
  IMPORTANT: Only the `NgFor` class is deprecated, not the `ngFor`
  directive. The `*ngFor` and related directives are unaffected by
  this change  as references to the `NgFor` class generated from
  templates will be automatically converted to references to
  `NgForOf<T>` without requiring any template modifications.
- `TrackByFn` is now deprecated. Use `TrackByFunction<T>` instead.

Migration:
- Replace direct references to the `NgFor` class to `NgForOf<any>`.
- Replace references to `TrackByFn` to `TrackByFunction<any>`.

BREAKING CHANGE:
A definition of `Iterable<T>` is now required to correctly compile
Angular applications. Support for `Iterable<T>` is not required at
runtime but a type definition `Iterable<T>` must be available.

`NgFor`, and now `NgForOf<T>`, already supports `Iterable<T>` at
runtime. With this change the type definition is updated to reflect
this support.

Migration:
- add "es2015.iterable.ts" to your tsconfig.json "libs" fields.

Part of #12398

PR Close #14104

modules/@angular/common/src/common_module.ts

@@ -8,14 +8,15 @@
 
 import {NgModule} from '@angular/core';
 
-import {COMMON_DIRECTIVES} from './directives/index';
+import {COMMON_DEPRECATED_DIRECTIVES, COMMON_DIRECTIVES} from './directives/index';
 import {NgLocaleLocalization, NgLocalization} from './localization';
 import {COMMON_PIPES} from './pipes/index';
 
+
 // Note: This does not contain the location providers,
 // as they need some platform specific implementations to work.
 /**
- * The module that includes all the basic Angular directives like {@link NgIf}, {@link NgFor}, ...
+ * The module that includes all the basic Angular directives like {@link NgIf}, {@link NgForOf}, ...
  *
  * @stable
  */
@@ -28,3 +29,10 @@ import {COMMON_PIPES} from './pipes/index';
 })
 export class CommonModule {
 }
+
+/**
+ * A module to contain deprecated directives.
+ */
+@NgModule({declarations: [COMMON_DEPRECATED_DIRECTIVES], exports: [COMMON_DEPRECATED_DIRECTIVES]})
+export class CommonDeprecatedModule {
+}