Group node

[SorsOps]

Group nodes as an action is currently working, however we are not saving the group at the moment as its not a core part of the graph engine.

We should add this as part of the saved serialized graph, and then hydrate the react flow nodes when loaded.

This would involve 2 steps.
1 Saving an annotation on the node identifying its parent group. This should happen on the grouping action
2. Serializing the grouping. This should happen as a finalizer for the graph.

Note that Reactflow demands that groups are defined first before other nodes. So you will need to extract the groups from the serialized nodes first and create them before the rest of the deserialization