Update shebang and error handling in entrypoint and healthcheck scripts

[NamrathShetty]

This pull request includes changes to multiple versions of MariaDB's docker-entrypoint.sh and healthcheck.sh scripts to improve compatibility and error handling. The most important changes involve updating the shebang lines and modifying the set command options.

[grooverdan]

shebang lines seem rather pointless as containers only have one defined environment where the full non-env path is correct.

On set - -Eu seems ok. I need more healthcheck.sh scripts for a greater confidence.

You may have seen, update.sh at top level will update per version files based on top level template file.

Please remove shebang changes, rebase to next and edit pr to target the next branch so some CI testing can be done on this.

[fauust]

On set - -Eu seems ok. I need more healthcheck.sh scripts for a greater confidence.

I don't see any problem with -E, -u is a very good thing but it's quite impacting, please make sure every part of the script has been tested before merging...