[!!!][TASK] Remove deprecated frontend-related hooks and include scripts

The following hooks have been removed:
- $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/index_ts.php']['preBeUser']
- $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/class.tslib_fe.php']['checkAlternativeIdMethods-PostProc']
- $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/class.tslib_fe.php']['checkDataSubmission']
- $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/index_ts.php']['preprocessRequest']
- $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/class.tslib_fe.php']['connectToDB']
- $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/class.tslib_fe.php']['hook_previewInfo']

The class EidRequestHandler has been removed.

eID targets cannot include a scriptpath anymore:
- $GLOBALS['TYPO3_CONF_VARS']['FE']['eID_include']['my_eID'] = 'EXT:benni/Scripts/download.php';

Instead, they must contain a target (callable, class/method, function).

The various hooks are still in place in deprecated methods within TSFE which will be removed
in the next patch. Also, now hardly usable PSR-15 middlewares will be cleaned up separately
as well.

Resolves: #87220
Releases: master
Change-Id: Ic54af83c97f2e6d2fba4346e382240d0fac6a2dc
Reviewed-on: https://review.typo3.org/59217


Reviewed-by: Benjamin Franzke <bfr@qbus.de>
Tested-by: Benjamin Franzke <bfr@qbus.de>
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>