I wonder if datalad-container should edit .datalad/.gitattributes when adding docker images to include

environments/**/*.json annex.largefiles=nothing
environments/*/image/repositories annex.largefiles=nothing

The json files are really small and better handled by git.
It would also avoid errors where the layers are already in the local docker service and can avoid pulling them from the repo, but still need the manifest to check for hashes.