Use rehosted downloads from storage box

[leonardehrenfried]

Fixes #416

[what-the-diff[bot]]

PR Summary

• Added OpenSSH client package The Dockerfiles in the 4.1 and 4.2 directories now include the openssh-client package.
• Adjusted retry configuration Changes were made to the retries configuration in the assert-non-empty-json file.
• Updated file transfer method in init.sh The init.sh files in the 4.1 and 4.2 directories have been updated to use sshpass and scp for file transfer, replacing the previous curl method. Additionally, download URLs for various files have been updated.