Recover sh support in Dockerfiles

rm /bin/sh && ln -sv /bin/bash /bin/sh

Does spark expect /bin/sh to be bash (in posix mode) and not just a generic posix compliant shell? Is there a bug with using dash? Minimally, this should do a dpkg --divert to ensure that users in dependent images don't accidentally revert it with package updates.

[1] https://github.com/docker-library/official-images/pull/13089?notification_referrer_id=NT_kwDOABp-orI0MzIwMzMwNzY5OjE3MzYzNTQ#issuecomment-1533540388
[2] related origina change: https://github.com/apache-spark-on-k8s/spark/pull/444/files