[!!!][TASK] Deprecate FormEngine::$renderReadonly

This patch deprecates FormEngine::$renderReadonly
and removes the dependency from all form element classes.

Resolves: #63847
Releases: master
Change-Id: I4c998c53a3d206586ce6c464696c6e6a4b2f99af
Reviewed-on: http://review.typo3.org/35500
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Alexander Opitz <opitz.alexander@googlemail.com>
Tested-by: Alexander Opitz <opitz.alexander@googlemail.com>
[!!!][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>
[!!!][TASK] Replace ExtJS DateTimePicker with bootstrap alternative

Follow-up: only deprecate unused method, not remove.

Resolves: #62925
Releases: master
Change-Id: Icce2e9756d74c1c3297fd57e125f67c27056b087
Reviewed-on: http://review.typo3.org/35580
Reviewed-by: Benjamin Mack <benni@typo3.org>
Tested-by: Benjamin Mack <benni@typo3.org>
[TASK] Re-add tests for renumberKeys

The test for renumberKeysToAvoidLeaps were accidentally
removed. Add them again.

Change-Id: Ib51cc8f96d7745ae199ecd2c1e77d728611fde78
Resolves: #63986
Releases: master
Reviewed-on: http://review.typo3.org/35582
Reviewed-by: Stephan Großberndt <stephan@grossberndt.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>