MIGRVDI-17: added check and migration for missing extension key as third parameter to \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addPlugin()
Merge branch 'feature/MIGRVDI-17'

* feature/MIGRVDI-17:
  MIGRVDI-17: added check and migration for missing extension key as third parameter to \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addPlugin()