Data overlay: cleanup zero bias selection scripts
This cleans-up zero bias selection scripts for data overlay. I tested scripts locally and all run, but more work will be needed to make them more configurable.
Note for shifters:
- these scripts are not tested in the CI as they query Oracle and EOS
- git might detect files as new unfortunately, I am open to suggestions for improvements but I'd rather do them in a follow-up MR so they can be tracked better
- I recommend hiding whitespace changes