add support to typo3 v11
typo3 v10 is maintained until beginning of 2023. typo3 V11 is maintained until october 2024. https://typo3.org/cms/roadmap/maintenance-releases
update nG6 extension source code to be compatible with typo3 V11
typo3 v10 is maintained until beginning of 2023. typo3 V11 is maintained until october 2024. https://typo3.org/cms/roadmap/maintenance-releases
update nG6 extension source code to be compatible with typo3 V11