[TASK] Add Site Configuration to ConfigurationController

Add the Site Configuration to the ConfigurationController to
simplify debugging and enable its inspection at the backend.

Resolves: #84709
Releases: master
Change-Id: Ib0720f372a2d27873fda9931c8753c7ed6a98750
Reviewed-on: https://review.typo3.org/56644


Reviewed-by: Mathias Brodala <mbrodala@pagemachine.de>
Tested-by: Mathias Brodala <mbrodala@pagemachine.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>