Establish first set of performance tests

We had only one ConceptServicePT that wasnt used in years (see linked issue). We removed it because it was outdated and not cared for.

We should establish performance tests that are run on a regular basis, or maybe integrated in the release plan.

Gather informations from the community on what is needed:

• gather requirements of performance tests/metrics we want to establish
• find a library that can achieve that and put it in place
• think about if/how we want to integrate that into the build/release process

Searching for Concepts and maybe Patient or Obs are probably good starting points but again check with community.