[FEATURE] ViewHelper to check feature flags

This patch adds a new condition-based Fluid ViewHelper which allows
integrators to check for feature flags from within Fluid templates.

Resolves: #104020
Releases: main
Change-Id: I76d19f4ec4888268b51fb9358812a870d79db41c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/84719


Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Garvin Hicking <gh@faktor-e.de>
Reviewed-by: Torben Hansen <derhansen@gmail.com>
Tested-by: Torben Hansen <derhansen@gmail.com>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Garvin Hicking <gh@faktor-e.de>