manager: run kresctl from the executor's working directory

manager: run kresctl from the executor's working directory

This updates `poethepoet` to version `^0.22.0`
(https://github.com/nat-n/poethepoet/releases/tag/v.0.22.0), which
allows tasks to have a working directory different from the project
path.

This breaks the `poe` script on Python `<3.8`, but discussions took
place on Slack where we came to the conclusion that this is fine. The
script is meant for developers only and does not affect end users on
systems that do not provide newer Python versions.