igx-date-picker and igx-time-picker doesn't handle required properly

[kdinev]

Description

The HTML validation doesn't pass through the igx-date and time pickers properly. Required doesn't put asterisk in the label, no red borders when touched and invalid, etc.

• igniteui-angular version: 8.2.14
• browser: all

Steps to reproduce

1. Create a date picker and mark it required.

<igx-date-picker label="Start Date"
                 name="startDate"
                 required
                 [(ngModel)]="tournament.StartDate">
</igx-date-picker>

Result

No visual indication in the component that it's required in the form.

Expected result

To behave like other form components.

[Lipata]

Added to the igxDateTimeEditorDirective specification.