Consider separating monolithic config into separate configs, allowing `nodebuilder.Store` to move to `nodebuilder/node.Store`

Move nodebuilder.Store to nodebuilder/node
* There is a dependency cycle with it, and the cycle just reveals the symptom of another problem - monolithic Config
* The Store has to be changed to allow storing Configs independently
```
Config(module string) (interface, error)
PutConfig(module string. interface) (error)
```
In both cases, the Config access can go either to the same file or different. depends on the implementation of the Store