Propagate summary state up the tree in GScan

[kinow]

Describe exactly what you would like to see in an upcoming release

As a follow-up, we should have a summary state propagate up the tree (so you can see if anything is running in a collapsed branch...)

Additional context

Follow-up from #502

Pull requests welcome!

[kinow]

Note on what must be displayed in the parent nodes to a workflow, via @hjoliver :

It should be job icons like the current workflow state totals, but made by combining the state totals all the workflows underneath. It's probably reasonable to just have the number of tasks for each item, and you can expand to tree to see the "recent tasks" info (otherwise we'd need to preface task ID with workflow name...)

So, in this "family" of workflows there are currently two failed tasks and six running etc.

[kinow]

From today's chat at Element with @hjoliver :

So we don't allow nested run directories, but we can have a directory hierarchy with workflows at multiple different levels ... >which means the aggregation result won't be the same at each level.
So as a first cut, maybe you should just display it at every level like in your screenshot above.

The screenshot mentioned: