jquery-datetimepicker: new package

This package provides datetimepicker, datepicker and timepicker
dropdown for web forms.

[Thomas:
  - add <pkg>_LICENSE_FILES.]

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>