cloudapi: save and return compose request details

The original compose request contains useful details that are not
preserved when it is converted to a manifest. Things like the
distribution, arch, image type, blueprint or customizations are useful
when examining builds later.

This saves the original request json using the job id and a new
directory (ComposeRequest) under the artifacts directory. The original
request, if present, is then added to the compose/<id>/metadata response
alongside the package list.

Related: RHEL-60120

internal/worker/server.go

@@ -676,6 +676,9 @@ func (s *Server) DeleteArtifacts(id uuid.UUID) error {
 		return fmt.Errorf("Cannot delete artifacts before job is finished: %s", id)
 	}
 
+	// Remove the ComposeRequest but ignore any errors
+	_ = os.Remove(path.Join(s.config.ArtifactsDir, "ComposeRequest", id.String()+".json"))
+
 	return os.RemoveAll(path.Join(s.config.ArtifactsDir, id.String()))
 }