[TASK] Mark LanguageService container entry as deprecated

Only the container entry – which acts as backend for
GeneralUtility::makeInstance(LanguageService::class) is
deprecated. The class is left as-is, but should be
factored via LanguageServiceFactory.

Therefore also all the factory methods are deprecated
in order for the LanguageServiceFactory to be used instead.

Resolves: #94414
Releases: master
Change-Id: Iab0f713a5baf95c419338748e8df4102d46c37a4
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/69367


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>