🏇 Job Board: Update preference model

In the Preference model:
1. Modify the years_of_experiences field
2. Add the work_schedule field
Fixed dependencies and tests according to the Preference model change.

Note: The main changes of the PR are in the Preference.py file and the 0004_test_data_years_of_experiences.py file. The rest are adjustments to the project following this change.

close #82

redhat-beyond / JobSeeker

🏇 Job Board: Update preference model #83