[TASK] Avoid usages to TSFE->sys_page

Since TYPO3 v9, PageRepository dependencies
are in better shape with the introduction
of Context API.

With TYPO3 v12, it is fully encapsulated
and can now be called and instantiated
when needed, instead of using TSFE->sys_page.

This patch migrates the last occurrences
in TYPO3 Core and only sets TSFE->sys_page
as b/w compat layer (deprecation later together
with other properties).

Resolves: #102723
Releases: main
Change-Id: I7a21ba28bfc0a22e4b980cc582c055864ebbaedd
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82276


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Sascha Nowak <sascha.nowak@netlogix.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>