Update the local node impl to deal with different kinds of UpdateDatas #360
Description
After completion of #167 the API now supports passing of related contracts data etc. but we are not currently supporting this at the node layer so we can track the requested updates or have different subscription modes for updates.
In practice only UpdateData::Delta is supported (as is equivalent to the previous API version).
After completing this issue we should be be able to handle different subscription modes and keep track/ask for the related contracts.