Option to hide tasks with uncompleted child tasks

[claremacrae]

Discussed in #1032

^{Originally posted by disser August 15, 2022}
In order to reduce clutter, it would be useful to hide tasks which have uncompleted child tasks:

• #task wash the car
  • #task find the 5gal bucket
  • #task clean the microfiber cloths

In the example above, "wash the car" is essentially a clutter item since it would appear as a top-level item, but I can't complete it without completing the child tasks, so I'd like to be able to hide them.

It would be more complicated to handle due/start dates on the parent task, but to me the intuitive behavior would be to have child tasks inherit from the parent.