[TASK] Show the "Today" button in DateTimePicker

This patch enable the "Today" button on the bottom of the DateTimePicker.
Clicking the "Today" button will set the date and time to now.

Resolves: #82723
Releases: master, 8.7
Change-Id: I262e0206754b2a9e785a6f1184712ba8cc26ad12
Reviewed-on: https://review.typo3.org/54396


Reviewed-by: Henning Liebe <h.liebe@neusta.de>
Tested-by: Henning Liebe <h.liebe@neusta.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Joerg Boesche <typo3@joergboesche.de>
Tested-by: Joerg Boesche <typo3@joergboesche.de>
Reviewed-by: Benjamin Kott <benjamin.kott@outlook.com>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>