Expose Central Staffing link for new installs and upgrades

Permissions have been updated to expose the Central Staffing link and screen. In upgrades, users in the SYSTEM ADMINS and SUPERVISORS groups are given EDIT permission only if the default permissions (DENY for SYSTEM ADMIN and SUPERVISORS groups) have not previously been changed. This allows users in the SYSTEM ADMINS and SUPERVISORS groups to access Central Staffing and use it to modify schedules.

For new installs, users in the SYSTEM ADMINS and SUPERVISORS groups are given EDIT permission for Central Staffing by default. The Staffing Center link is also hidden for all security groups in new installs.