Add support to return all runs from a given config

[Wegatriespython]

Currently src/climate_assement/post_process.py computes a set of percentiles. The relationship between the config params and the resulting output is not available. It would be desirable to have an option return_all_runs which would give a row for each run_id. I have a branch with this patch and can make a PR if I can be granted access to push.

[jkikstra]

Indeed - this would be a nice additional option (I know some actually use it like this locally as well).
Would be great if you can make that PR 👍