a11y: Improve time-picker accessibility

[desig9stein]

Description

Provide an accessible experience for igx-time-picker.

Consider adding some of those roles:
-spinbutton
-presentation
-region

We also need aria-label on the groups HH.MM.AM.

NOTE: We need to trap the focus inside the time picker dialog.

• igniteui-angular version: 11.1.x
• browser: all

[Lipata]

We've updated ARIA sections of both igxDatePicker and igxTimePicker components, using the suggestions above and ARIA will be done as part of their refactoring.