Set supervisees of a position

[Shannon Turlington]

Enable all of the supervisees of a supervisor to be selected from the supervisor's position. We may write another use case for choosing supervisors/supervisees of a position, such as show all current assignments with position and Employee name, if the position is filled; change or select Supervisor (only one allowed); change or select subordinate (several allowed). For now, users can only select the Supervisor's position from the Position form.