TYPO3 11 compatibility release. Changes:

 updated requirements (TYPO3 10-11, PHP 7.4-8.0)
 adjusted extConf loading related to deprecation 82254
 adjusted extension configuration related to deprecation 92947
 converted translation files from llxml to xliff
 updated documentation structure

Another minor release will follow after the TYPO3 11 LTS release in October. Follow its development at https://gitlab.com/opsone_ch/typo3/varnish/-/boards.