Add process ID management in fixtures for testing performing server management and clean-up

[PProfizi]

Description of the feature

To allow properly running test modules in parallel, we can add process ID management for gRPC servers. This way a test would only make sure it kills the server processes it started and not all Ans.Dpf.Grpc processes.

PS: just a reminder that this is specific to test modules extensively starting and killing gRPC servers, as tests using InProcess cannot kill it. They all use the same (something to think about too).

Steps for implementing the feature

No response

Useful links and references

No response