[BUGFIX] Set current time as default in flatpickr

flatpickr always defaults to 12:00 if no other value is given, being
quite inconvenient. The options `defaultHour` and `defaultMinute` are
now provided to set the current time when opening flatpickr on an empty
input field.

Resolves: #97798
Releases: main, 11.5
Change-Id: Ic222c2ff0e3bf111c498c16dd27ecdc703909342
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75086


Tested-by: core-ci <typo3@b13.com>
Tested-by: Nikita Hovratov <nikita.h@live.de>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Oliver Bartsch <bo@cedev.de>