feat(MatDateRangePicker): add ability to use a custom component inside a dialog/popup

#### Feature Description

At the moment, the component that is used by the [`MatDatepickerBase._openAsDialog`](https://github.com/angular/components/blob/dfdf5cf7574a201b98b7e35ce770984527c790ee/src/material/datepicker/datepicker-base.ts#L500) and [`MatDatepickerBase._openAsPopup`](https://github.com/angular/components/blob/dfdf5cf7574a201b98b7e35ce770984527c790ee/src/material/datepicker/datepicker-base.ts#L542) methods is hardcoded. And you can't extend those because they are private.

If, instead, `MatDatepickerContent` was injected, we would have the ability to provide a component with extended functionality, e.g. with predefined date ranges. So, in the `MatDatepickerBase` we should have something like that:
```ts
constructor(
// ...
@Inject(MAT_DATEPICKER_CONTENT) private datepickerContent: MatDatepickerContentBase,
) {
// ...
}

// ...

private _openAsDialog(): void {
// ...
this._dialogRef = this._dialog.open>(this.datepickerContent, /* ... */);
// ...
}
```

We can then import `MatDatepickerContentBase`, extend it and provide our own component to be used in a dialog or popup.

#### Use Case

Add predefined ranges, use two calendars instead of one, add buttons etc.
For example, check the [ngx-daterangepicker-material](https://www.npmjs.com/package/ngx-daterangepicker-material) package:

Beginne mit dem Lesen von src/material/datepicker/datepicker-base.ts bei _openAsDialog und _openAsPopup und verfolge dann MatDatepickerContent und MatDatepickerContentBase. Definiere den injizierbaren Erweiterungspunkt für Inhalte und überprüfe, dass eine benutzerdefinierte Komponente den fest codierten Dialog- oder Popup-Inhalt ersetzen kann und dabei das datepicker-Verhalten beibehält.

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