[TASK] Add LanguageAspect to Contexts

This change adds a new Aspect called "Language" which bundles
most existing TypoScript options on frontend language fetching.
A factory allows to migrate the logic from TSFE.

Major / Important Changes:
- RootlineUtility is decoupled from PageRepository
- TSFE->sys_language_mode is not necessary anymore
- TSFE->sys_language_contentOL can be substituted by "overlayType" of Aspect
- A new PageRepository->getLanguageOverlay() bundles all other methods
- A lot of common public properties in TSFE are now deprecated

Next steps:
- Isolate calls from RootlineUtility/PageRepository more from each other and from TSFE
- Migrate PageRepository "-1" parameters to "null"
- Migrate usages PageRepository->getRootline() to RootlineUtility::__construct()
- Then deprecate PageRepository->getRootLine()
- Migrate Extbase QuerySettings to Contexts

Resolves: #85543
Releases: master
Change-Id: I8d177222a244a8d1fd66a884e9fc50b107f27e20
Reviewed-on: https://review.typo3.org/57424


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>