feat(common): Add and enable the Intl implementation for the i18n sub…

…-system.

Angular's i18n subsystem is responsible for providing localised formatting of numbers, percents, percentages and dates.
This feature replaces the default implementation of the i18N subsystem.

The new implementation relies on the platform-provided [`Intl` API](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl).

With the formatting now relying on a platform API, it is not necessary anymore the load locale files (See #20487) .

* For numbers, percents and currencies, the `Intl` implementation replaces the exisiting one.
* For dates, the feature is being introduced as an **opt-out** : `useLegacyDateFormatting()`, new application will rely on the Intl implementation by default.
  *  Existing applications will be migrated to opt-out of this change and rely on the previously existing implementation.

BREAKING CHANGE: Formatting output might be altered for dates.
* Expect changes for formats `cccccc`, `EEEEEE`, `aaaaa`, `b` to `bbbbb` and `B` to `BBBBB`. Extensive details are available in the changes of `format_date_spec.ts`.
* The `DatePipe` will not support offset `timezone` anymore, use IANA timezones instead .

goldens/public-api/common/index.md

@@ -167,7 +167,7 @@ export class DecimalPipe implements PipeTransform {
 export const DOCUMENT: InjectionToken<Document>;
 
 // @public
-export function formatCurrency(value: number, locale: string, currency: string, currencyCode?: string, digitsInfo?: string): string;
+export function formatCurrency(value: number, locale: string, display: 'code' | 'symbol' | 'symbol-narrow' | string, currencyCode?: string, digitsInfo?: string): string;
 
 // @public
 export function formatDate(value: string | number | Date, format: string, locale: string, timezone?: string): string;
@@ -895,7 +895,7 @@ export const provideImgixLoader: (path: string) => Provider[];
 // @public
 export function provideNetlifyLoader(path?: string): Provider[];
 
-// @public
+// @public @deprecated
 export function registerLocaleData(data: any, localeId?: string | any, extraData?: any): void;
 
 // @public
@@ -958,6 +958,9 @@ export class UpperCasePipe implements PipeTransform {
     static ɵpipe: i0.ɵɵPipeDeclaration<UpperCasePipe, "uppercase", true>;
 }
 
+// @public (undocumented)
+export function useLegacyDateFormatting(): void;
+
 // @public (undocumented)
 export const VERSION: Version;
 

packages/common/src/common.ts

@@ -16,13 +16,12 @@ export * from './location/index';
 export {formatDate} from './i18n/format_date';
 export {formatCurrency, formatNumber, formatPercent} from './i18n/format_number';
 export {NgLocaleLocalization, NgLocalization} from './i18n/localization';
+export {useLegacyDateFormatting} from './i18n/format_date';
 export {registerLocaleData} from './i18n/locale_data';
 export {
   Plural,
   NumberFormatStyle,
-  FormStyle,
   Time,
-  TranslationWidth,
   FormatWidth,
   NumberSymbol,
   WeekDay,
@@ -48,6 +47,7 @@ export {
   getLocaleCurrencySymbol,
   getLocaleDirection,
 } from './i18n/locale_data_api';
+export {FormStyle, TranslationWidth} from './i18n/format_date_interface';
 export {parseCookieValue as ɵparseCookieValue} from './cookie';
 export {CommonModule} from './common_module';
 export {