TYPO3 Core

Now that we have site settings, it should be possible to configure conditions for them.
The syntax should be the same as for form variants (see https://review.typo3.org/c/Packages/TYPO3.CMS/+/54982/ )

Variants should for now be only configurable when directly editing the file (no GUI for now) - but the GUI must not overwrite variants.

Base use cases that should be possible:
- set different values based on language configuration (for example: different values for Lang 0 or 1)
- set different values based on extension load state (for example: isLoaded('news')..)
- set different values based on application context

Make sure the syntax for the use cases - if similar things exist - stays the same in all contexts (for example the first one should allow siteLanguage.getLocale() == "de_DE" as used in form and probably TS conditions)

Example settings.yaml:

MyVendor:
    MyExtension:
        storagePid: 15
        limit: 10
        variants:
              -
                identifier: EnglishOnly
                properties:
                     storagePid: 16
                     limit: 15
                condition: 'siteLanguage.getLocale() == "en_US.UTF-8"'
              - 
                identifier: DevelopmentContext
                properties: 
                     limit: 1000
                condition: 'applicationContext matches "#Development#" 
             -
                identifier: NewsIsLoaded
                properties:
                    bar: bar
                condition: 'isLoaded("news")'