Implemented changes after review

Classes/Controller/JoblistController.php

Classes/Domain/Model/Job.php

Classes/Domain/Model/JobApplication.php

Classes/Domain/Repository/JobRepository.php

Configuration/FlexForms/Joblist.xml

Configuration/TCA/Overrides/tt_content.php

Configuration/TCA/tx_sgjobs_domain_model_job.php

Configuration/TypoScript/Backend/constants.ts

Configuration/TypoScript/Backend/setup.ts

Configuration/TypoScript/Frontend/constants.ts

Configuration/TypoScript/Frontend/setup.ts

Configuration/TypoScript/constants.ts

Configuration/TypoScript/setup.ts

Resources/Private/Language/de.locallang.xlf

Resources/Private/Language/locallang_backend.xlf

Resources/Private/Partials/Job.html

Resources/Private/Templates/Joblist/ApplyForm.html

Resources/Private/Templates/Joblist/Index.html

Resources/Public/JavaScript/fileAjax.js

ext_localconf.php