Allow for the ability to exclude individual users from timesheets

[#1]

As you know, timesheets are created automatically for all users even when a user does not have a timesheet profile. Some users don't need to track time (e.g., people who only review work items). Additionally, this also impacts our ability to send time sheet reminders at the system level since they go to all users.

It would be great to have the ability to exclude certain users from having timesheets created for them in the system so that they don't show up on open timesheet reports and don't receive system level timesheet reminders.