(web) service revision - renaming WebService(Version) to DigitalService(Version)

[lzehl]

Not all digital services are web services. I would like to bring them together.
Their exact type (e.g. "web service", "system service", etc) should be an annotation.

This would also pave the way towards other service types which need totally different schemas.
E.g. HumanService(Version) (e.g. Curation, etc) or HardwareService(Version) (e.g. service to a specific hardware, e.g. scanner, neuromorphic chip, etc) etc.

We need to discuss general service types (and which of them have joined or very similar metadata).