Reinstate s390X Container Support

[dixonwhitmire]

The 0.57.0 release supports images for s390x, amd64, and arm64 within a single image repository, thanks to docker buildx and "manifests".

With the 0.58.0 release the official Python image no longer supports s390x.

To continue support for s390x we will need to determine if we can still support all architectures within our single image tag. Additionally need to review how we are installing Fast API and Uvicorn in the container image. Specifically, if "watchfiles" is included we also need to include the rust runtime. We would like to avoid this dependency if possible as it reduces our build complexity. However, rust will be required for Pydantic v2 (still a long way off from releasing).