Feat(pipeline): create initial pipeline implementation

[ChrisRousey]

This PR is for the implementation of the Datacater Pipeline Concept.

• Messages are to be consumed from the definded stream-in
• Forwarded to a Datacater Python-runner
  • Here, it is processed (transformed and or filtered)
• The processed message is produced to the defined stream-out

The defined test will currently not work, as there is a bug in the currently deployed python-runner on the /batch endpoint. I fixed the endpoint in the PR.

To test manually, the python runner and be run locally:

1. pip3 install -r requirements.txt
2. python3 -m uvicorn runner:app

And by then setting environment variables:

• DATACATER_PYTHONRUNNER_PORT=8000
• DATACATER_PYTHONRUNNER_HOST=localhost

[HknLof]

Thanks for the feature :)