rename client to consumer

[MoritzKeppler]

Suggest to replace "client" by "consumer" in the extensions code as this term is used in IDS and Gaia-X documents.
Also feels more natural to have the pair "provider & consumer" instead of "provider & client".
What do you think?

[paullatzelsperger]

the client contains a CLI client to interact with a connector, so I think the term "client" is indeed warranted there, but in general I agree, "consumer" or "consuming connector" is a good name.

[jimmarino]

+1 Should we do this before or after the Eclipse move? I think it is a change we could do relatively quickly but we may need to make sure there are no pending branch merges that need to be done.

What do people think? I'd be willing to go through and try and change the names in one shot.

[MoritzKeppler]

I'm fine with both doing it before we move to Eclipse or afterwards - but I don't have open branches to merge so my vote does not count.