Adds jQuery datepicker widgets to Drupal 8.
Originally was part of the Tieto Modules umbrella package.
In 2.1 the static "tieto_date" format was removed, the value is now taken from config. The default for that has been set to "medium". Sites relying on the "tieto_date" format have to manually set the "date_format" config key back to "tieto_date".