Improve Node.CachedData

Previous version was analogous to what we were
doing before but there is a palce for some improvements:
- since we have batched requests, we don't have to call
  API separately for config, dgpo or network type, because
  everything can be done in a batch (GetNodeBasicInfo cmd)
- when changing node address, sync is required on a next property access
  and when there are many calls to accessor, update can be triggered
  multiple times. Now lock prevents that and multiple asycnio tasks will wait
  for a single data update to end.
- dgpo/config update is done in a more controlled way, via update method