[!!!][TASK] Replace ExtJS DateTimePicker with bootstrap alternative

This patch replaces the ExtJS DateTimePicker with a bootstrap
based alternative.

The DatePicker is used in the EXT:belog module,
FormEngine and in the EXT:scheduler module

Resolves: #62925
Releases: master
Change-Id: I012e907dda7b8ab0f8583bab2c55cff82c93179e
Reviewed-on: http://review.typo3.org/34094
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>