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.