Support of TYPO3 12

With 7.0.0 TYPO3 11 & 12 are supported. Support of TYPO3 10 has been dropped!

What's Changed

• [TASK] Align with new TYPO3 documentation standards by @alexander-nitsche in #411
• [TASK] Align with new TYPO3 documentation standards (follow-up) by @alexander-nitsche in #413
• [FEATURE] Added storage page check for showAction by @derhansen in #415
• Apply fixes from StyleCI by @georgringer in #418
• [TASK] int cast for pid value by @ayacoo in #419
• [TASK] Migrate 1st run by @georgringer in #424

Full Changelog: 6.1.0...7.0.0