The current local development environment for Toolhub uses curl to call blubberoid and generate a Dockerfile which is then used from the docker-compose.yaml to build the runtime container for Toolhub itself. Now that Blubber publishes a buildkit frontend, we can use it rather than blubberoid.

This will look something like:

• Add a # syntax=docker-registry.wikimedia.org/wikimedia/blubber-buildkit:<some tag> directive to the top of .pipeline/blubber.yaml
• Change "dockerfile" values to .pipeline/blubber.yaml
• Add "target" values to appropriate blubber variant names
• Remove legacy .pipeline/*.Dockerfile files
• Remove legacy Makefile instructions for generating .pipeline/*.Dockerfile files