Broker datapoints interface to retrieve metadata should include data type unit

[erikbosch]

This issue originates from eclipse-kuksa/kuksa.val.services#102 but moved here as it concerns Databroker

The data unit types of VSS should be exposed via GetMetadata as well.

Eg when subscribing to "Vehicle.Speed", the value is in "km/h" as specified. Since the spec can be overriden, it's hard for generic tools ("VSS Browser") to know the specific data type unit, unless it is exposed via the metadata interface.

[lukasmittag]

at least we have this #726 but yes would be good to have unit also shown in getMetaData call agree!

[erikbosch]

We are about to archive this repo soon. If you consider this issue as important please file a new issue at one of the new Kuksa repos at https://github.com/eclipse-kuksa