Begin of the insertionPart of ##40867

Motivation: 

* The work package attributes for % Progress for a work package has two values:
* TheEnd of the insertion Begin of the deletion Second phase is to have "% Complete" computation being done consistently according to "Work"End of the deletion value Begin of the insertionfor the the parent work package itself.
* The aggregated value, derived from the work packageEnd of the insertion and Begin of the insertionits children attributes (before it was children attributes only)
* The derived value computation depends onEnd of the insertion Begin of the deletion children's values, orEnd of the deletion the Begin of the insertionwork, the status, and the % progress attributes of theEnd of the insertion work Begin of the insertionpackages
* closed status means 100% progress
* a workEnd of the insertion package Begin of the insertionwith work being 0h or unset is excluded from computation

See subtasks belowEnd of the insertion Begin of the deletion status.End of the deletion