- major structure change in DataBundle. Moved different services and their additional files to subfolders with sub namespaces.
- renamed all services with appropriate names
- made extra service for Job object
- DataService.php is only parent class for salesforce interface access and some commonly used functions
=> still not finished with all the structural changes. Some services and their helper files are still not put in subfolders.

- deleting offered timeslots now works

- added unit test for Timeslot object (might still not be complete but is first template for similar tests that should be performed on every object class)