Ingest the contents at the given path path into castore, and registers the
resulting root node in the passed PathInfoService, using the “NAR sha256
digest” and the passed name for output path calculation.
Inserts the PathInfo into the PathInfoService and returns it back to the caller.
The name should have been checked by nix_compat::store_path::validate_name
before, to avoid unnecessarily importing, but will prevent the PathInfo from
being created in case of an invalid name.