[TASK] RecordListController: Merge init() and main() to mainAction()

Merge the methods `init()` and `main()` to the `mainAction()` method.
Remove unnecessary properties, which were only used to transfer values
between these methods.

Initialize `siteLanguages` with the current page uid.

Releases: master
Resolves: #92308
Resolves: #90966
Change-Id: Iafd45ebeb06e8c61dac9e9ed865e40bc999ab54a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/65739


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>