replace wrk with p0d in J8a's ci/cd

[simonmittag]

[simonmittag]

for starters, let's replace the current config of wrk with p0d, keeping the same set-up and the same level of concurrency afterwards.

• [ ] record mean performance metrics from last few runs
• [ ] install homebrew for linux
• [ ] install p0d from homebrew
• [ ] use p0d with the same config wrk currently uses for all jobs
• [ ] store p0d results as artefacts in circleci build
• [ ] pass/fail test with threshold remains and needs to be re-implemented in circleci.
• [ ] remove wrk artefacts and lua scripts.

[simonmittag]

@MayankGandhe can you start working on this please?