[TASK] Centralize CgiServer check in Environment API

"GeneralUtility::isRunningOnCgiServerApi()" is now deprecated
in favor of "Environment::isRunningOnCgiServer()".

Resolves: #90800
Releases: master
Change-Id: Ib9e9e38d0e53ca00f3c58eb3255943d57cf7c0e0
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63680


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Daniel Haupt <mail@danielhaupt.de>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Daniel Haupt <mail@danielhaupt.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>