Migration of Image Archive Compression Format to zstd

As part of our ongoing optimization efforts, we are migrating the compression format of our image archives from tar.gz to tar.zst (zstd) to significantly reduce installation times. The file extension of the archives has changed accordingly.
If you are operating an automated installation environment and reusing existing installimage configurations, we kindly ask you to review the respective IMAGE parameter and update the file extension to reflect the new tar.zst format.