[WIP][TASK] NL-3241 Add menu builder forms

.gitignore

Classes/Domain/Model/Menu.php

Classes/Domain/Model/MenuItem.php

Classes/Domain/Model/MenuItemContent.php

Classes/Domain/Model/MenuItemLink.php

Classes/Domain/Model/MenuItemPage.php

Configuration/Extbase/Persistence/Classes.php

Configuration/ExtensionBuilder/settings.yaml

Configuration/TCA/tx_nlmenubuilder_domain_model_content.php

Configuration/TCA/tx_nlmenubuilder_domain_model_link.php

Configuration/TCA/tx_nlmenubuilder_domain_model_menu.php

Configuration/TCA/tx_nlmenubuilder_domain_model_menuitem.php

Configuration/TCA/tx_nlmenubuilder_domain_model_page.php

Configuration/TCA/tx_nlmenubuilder_domain_model_submenu.php

ExtensionBuilder.json

Resources/Private/Language/locallang.xlf

...e/locallang_csh_tx_nlmenubuilder_domain_model_content.xlf

...uage/locallang_csh_tx_nlmenubuilder_domain_model_link.xlf

...uage/locallang_csh_tx_nlmenubuilder_domain_model_menu.xlf

...locallang_csh_tx_nlmenubuilder_domain_model_menugroup.xlf