Datepicker needs to allow for setting today's date.

[dsarosi]

The today's date highlighting is controlled by the widget, which means it uses the browser's timezone to get the current data. Unfortunately, this doesn't work for system where user sets their time zone on the server independent of the client. For example business travelers may be in different timezones but use their home timzone as reference. Thus we need a function to set the today's date in the widget.

[Scott González]

Duplicate of #5427.