Need to extract all this logic in to separate class NeutronNetworkSerializer and for nova network NovaNetworkSerailizer.
In this class should be simple switcher between network serializers.
I think this class should accept list of nodes and cluster which need to serialize. 
And returns same structure

```
{
    "common": {"attr": 1, "attr2": 2},
    "individual_for_nodes": {
        "node_uid_1": {"attr_for_node1": 1, "attr_for_node1": 2},
        "node_uid_2": {"attr_for_node2": 1, "attr_for_node2": 2}
    }
}
```

And then you take this structure and merge it with data for exact node (depend on keys in `individual_for_nodes`) then merge common attr for each node.

@enchantner what do you think?