bake: Support named build contexts

bake: Support named build contexts: a task in LegoFlow-SWE (Harbor dataset). The bake command does not support named build contexts (the --build-context flag available in docker build ). Only the main build context can be specified via the context key. There is no way to define additional named…

The task

The `bake` command does not support named build contexts (the `--build-context` flag available in `docker build`). Only the main build context can be specified via the `context` key. There is no way to define additional named contexts like `image` or `import` that Dockerfiles can reference with `FROM` or `--from`.

Part of Lego-X/LegoFlow-SWE.