[TASK] Initial commit with skeleton

Classes/Controller/ListController.php

Classes/Controller/ModerationController.php

Classes/Domain/Model/Base.php

Classes/Domain/Repository/BaseRepository.php

Classes/Service/ModerationService.php

Classes/ViewHelpers/AbstractViewHelper.php

Classes/ViewHelpers/AddJavaScriptFileViewHelper.php

Classes/ViewHelpers/Backend/ControlViewHelper.php

Classes/ViewHelpers/Backend/EditOnClickViewHelper.php

Classes/ViewHelpers/Backend/IconViewHelper.php

...wHelpers/Backend/Widget/Controller/PaginateController.php

Classes/ViewHelpers/Backend/Widget/PaginateViewHelper.php

Classes/ViewHelpers/InlineLanguageLabelsViewHelper.php

Classes/ViewHelpers/SetViewHelper.php

Classes/ViewHelpers/Widget/UriViewHelper.php

...guration/TCA/tx_sgextensionskeleton_domain_model_base.php

Configuration/TypoScript/Backend/constants.txt

Configuration/TypoScript/Backend/setup.txt

Configuration/TypoScript/Frontend/constants.txt

Configuration/TypoScript/Frontend/setup.txt