[re #12160] Added mapping of status_classification
- Removed code that was by mistake added into some repository last MR (my bad)
- Created new service for Work_unit
- Created service for status
TLDR: After that, we are able to successfuly map status.name to status_classification, status repository is prepared to save statuses (we need to ask before Mr. Pícha couple of questions if I get the mapping right) I also prepared (most of the) saving of nto foreign key columns in work_unit