Improve handling microservice configuration

[eikek]

The configuration is currently often read multiple times from each service. It might be nicer, to read it only once and pass down case classes to where the information is required.

It could be one giant config object passed down everywhere, or reflect a bit the tree structure of the dependencies between the objects.

Expected advantages:

• no need to depend on the concrete config library "everywhere"
• easier testing by instantiating config literals