[TASK] Almost fixed file upload foo

Classes/Controller/JoblistController.php

Classes/Domain/Model/FileReference.php

Classes/Domain/Model/JobApplication.php

...Property/TypeConverter/UploadedFileReferenceConverter.php

Configuration/TCA/tx_sgjobs_domain_model_job_application.php

Configuration/TypoScript/Frontend/setup.ts

README.md

Resources/Private/Language/de.locallang.xlf

Resources/Private/Language/de.locallang_db.xlf

Resources/Private/Language/locallang.xlf

Resources/Private/Language/locallang_db.xlf

Resources/Private/Templates/Joblist/ApplyForm.html

ext_tables.sql