Kong2022/examples/readme: set $CBIG_CODE_DIR env missing

[0nu]

The $CBIG_CODE_DIR env variable has to be set to (correctly) run KONG2022/examples/CBIG_ArealMSHBM_create_example_input_data.sh. This info is missing in examples/readme.md. If not set, the script doesn't terminate but just throws some warnings and probably copies things to a wrong location.

Might make even more sense to just read the scripts directory via SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd ) or sth like this.

[rubykong]

@0nu Thanks for the suggestions! I think I will add a check for this environment variable and throw error messages. Will update in our next release.