ci.yml: Check that all services can build and start via Docker

[s-heppner]

Currently, our ci.yml only checks the repository server.
With the newly added different service definitions (e.g., registry and discovery), we need to add them as well to be checked.

Furthermore, we should check that the server Python package build, similar to sdk.

Lastly, the ci.yml is very large at this point. Maybe it makes sense to split it up into the different packages of the mono-repository?