✨NEW: Deal with more complicated "from group" cases

[mbercx]

Currently, the FromGroupSubmissionController can only have one process per node in the parent group, since it exclusively keeps track of what is submitted via the extras defined on the parent nodes.

However, there may be use cases where we want to run the same parent node with different settings, and want to keep track of that. A common example is a convergence study: we want to test different parameters for each structure in a parent group.

One way would be to have another "extras" field on a controller and add both to each work chain. Will have to think a bit on how to best implement this so it's user friendly, but it seems pretty straightforward at first glance.