Currently, one needs to specify the `unique_extras` to uniquely identify the parent nodes in the `parent_group`. This logic can cause some limitations, e.g. in the context of convergence studies. In such scenarios, one wants to submit several calculations (with different parameters) for a certain parent node.

Here, the concept of `dynamic_extra`s is introduced. These extras are not used to identify a parent node but rather to identify a certain result, e.g. a `WorkChain` with certain parameters.

Moreover, the `uuid` is used as the attribute that defines a parent node in the `FromGroupSubmissionController`. The `unique_extra_kyes` can still be used to take advantage of passing the extras between the parent node and the result node, but they become optional in this version.