Registry synchronization between remote instances

[DivineThreepwood]

It would be a nice feature to provide a registry remote synchronization between other remote instances to reduce single point of failures.

For this, the RegistryDataTypes need to be extended with a Timestamp field which is only modified and updated by the main controller. In case the registry data changes the timestemp is updated with the current time. In case the remote registries requesting the registry data and no main controller is responding (remote not connected) remote registries which have already a synchronized data field providing this data by publishing this on on the unit status scrope via informer. By this the non connected remote instances can filter the received data set by choosing the one with the latest timestemp.