[TASK] Simplify TSFE->settingLanguage

$TSFE->settingLanguage() resolve possibly language
overlays when a page is accessed. This method
has been around for a long time, and with the introduction
of Site handling and its language handling, this method
can be simplified.

* sys_page->getPageOverlay() now is handed in the full default
  language record which is tried to be overlaid, but also
  resolves the full fallback chain.
  This way, including all the caching information from sys_page
  is used, TSFE does not need to retrieve the full record
  from sys_page->getPageOverlay() manually anymore.
* FallbackChain "ignore" can be removed, as it is not possible
  anymore since at least TYPO3 v10 to ignore the fallback
  logic, and the condition can be removed.

Resolves: #99711
Releases: main
Change-Id: I056e12f1a2d0805eb9c9cfb211a37fb83974c661
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/77422


Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>