DatePicker: Allow setting of HTML id tag on popup

[ryc76]

Is your feature request related to a problem? Please describe.
Due to the auto generated id tags attached to the DatePicker popups it is very difficult to create automated UI tests that can select the day of the month when you have multiple DatePickers on a single page.

Describe the solution you'd like
An attribute that allows the setting of the id HTML attribute on the outermost div on the popup

Describe alternatives you've considered
Tried using the existing "id" attribute but that is only attached to the input field attached to the popup, not the popup itself.

Additional context