Remove jobs from registry.Service

This makes `registry.Service` a first class type and does not use jobs
to interact with this type.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

graph/pull.go

@@ -35,7 +35,7 @@ func (s *TagStore) CmdPull(job *engine.Job) error {
 	)
 
 	// Resolve the Repository name from fqn to RepositoryInfo
-	repoInfo, err := registry.ResolveRepositoryInfo(job, localName)
+	repoInfo, err := s.registryService.ResolveRepository(localName)
 	if err != nil {
 		return err
 	}