Import Mapping: Ability to run custom code

src/Application/Twig/AppExtension.php

src/Biopen/CoreBundle/Command/MigrationCommand.php

src/Biopen/GeoDirectoryBundle/Admin/ImportDynamicAdmin.php

src/Biopen/GeoDirectoryBundle/Document/Import.php

...oDirectoryBundle/Services/ElementImportMappingService.php

...open/GeoDirectoryBundle/Services/ElementImportService.php

web/assets/js/ace/mode-php.js

web/assets/js/ace/worker-php.js

web/test.json