[TASK] Clean up site configuration functionality

This cleans up several details in the site configuration handling,
especially in terms of caching.

* Remove SingletonInterface from `SiteConfiguration`
* Replace @internal properties with constants
* Use injected services instead of duplicated makeInstance() calls
* Replacing property based cache with runtime cache in `SiteConfiguration`

Resolves: #105263
Releases: main
Change-Id: Idbcd9553b1fa65ca5781ef838f12157a5024a349
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/86546


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>