Publish S3 backend container image

[paulkre]

This pull request modifies the CI pipeline to publish a separate container image ghcr.io/umessen/dicom-rst-s3:vX.X.X which has the S3 backend feature enabled.

[nickamzol]

Minor request regarding the image version, otherwise this looks good to me.

I think we should introduce a -full image just for convenience if you want to try out all available backends.

• -full with all features enabled
• -s3 with the S3 feature enabled
• -dimse in the future when we make the DIMSE backend optional.

The removal of cargo-chef will increase the build time, but I understand that there are some issues with distroless images and TLS introduced by the S3 dependencies. Nothing critical though - we can always improve it later on.

[paulkre]

I agree that we should publish a full version of the image with all features. I would even argue, we don't necessarily have to publish any images other than the full version. If users want specialized images with a subset of features, they can always build their own image. But I chose this solution because I wasn't sure yet, whether the S3 backend is ready for production use.

But even if we want to publish additional images, we should do this in a separate PR, in my opinion.