Currently, we have a confusing setup in our sample settings config file, where we have a date format and datepicker format, which are in slightly different formats. This can be confusing for an administrator to determine what to set for those settings to get the desired configuration. There seems to be no reason why there are two settings, as an administrator would likely set them to show in the same format.
To remove this confusion:
Remove the datepicker format and just have one date format (and one datetime format) in the settings sample.
Provide some code, if necessary, to translate the date format (from reference data that is stored in the locale service) into a date format that the datepicker can use.
Refactor the datepicker directive (in ui-components) to use the date format, or the DEFAULT_DATE_FORMAT if the date format is not found, using the code provided in the previous item
The datepicker format is no longer in the sample settings env file
The datepicker code in the UI uses the date format in the sample settings env file