The county may establish and prescribe for all employees of the county the following provisions applicable to such employees:
1. Normal workdays and hours of employment therein;
2. Holidays;
3. Days of vacation allowed;
4. Days of sick leave allowed;
5. Other provisions concerning the hours and conditions of employment;
6. Plans of personnel management and control.
The county may establish, alter, amend or repeal at will any provision adopted under this section.