Ability to schedule Timesheet recency items future completion

Raised on behalf of Andrea Turnbull for Flight Options.

They currently use timesheet items as requirements for their scheduler tasks.
This is causing an issue as the timesheet items are expiring before the task start date, wich causes the pilot to not appear in the drop-down list as a resource.

In order to use Timesheet items for task requirements, they will need to be able to schedule them so that the pilots remain selectable.