Add jQueryUI datepicker formatting options

[Phil-G]

Looking to replace the jQueryUI datepicker with this one. We're able replicate the different options except for the date format. It would be great to add more formatting options such as day/month names. For reference, see https://api.jqueryui.com/datepicker/#utility-formatDate D/DD, M/MM is what we're looking for.

[fengyuanchen]

I have to point out that this project is being deprecated.