[TASK] Doctrine: Introduce backend query context to exclude Placeholders

This patch adds a new query context BACKEND_NO_VERSIONING_PLACEHOLDERS
that de-selects versioning placeholders from other workspaces in the
same way that BackendUtility::versioningPlaceholdersClause() does. Usage
as follows:

$queryBuilder
  ->getQueryContext()
  ->setContext(QueryContextType::BACKEND_NO_VERSIONING_PLACEHOLDERS)
  ->setCurrentWorkspace(4);

Releases: master
Resolves: #75821
Change-Id: Iaa238f3da803c6d2dd23f0240cb2c409a39eec58
Reviewed-on: https://review.typo3.org/47827


Reviewed-by: Jonathan IROULIN <joniroutypo3@gmail.com>
Tested-by: Jonathan IROULIN <joniroutypo3@gmail.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>