Split CRI image service from GRPC handler

Prepares the CRI image service for splitting CRI into multiple plugins.
Also prepares for config migration which will spread across multiple
different plugins.

Signed-off-by: Derek McGowan <derek@mcg.dev>

pkg/cri/server/podsandbox/controller.go

@@ -103,10 +103,9 @@ type CRIService interface {
 
 // ImageService specifies dependencies to CRI image service.
 type ImageService interface {
-	runtime.ImageServiceServer
-
 	LocalResolve(refOrID string) (imagestore.Image, error)
 	GetImage(id string) (imagestore.Image, error)
+	PullImage(ctx context.Context, name string, creds func(string) (string, string, error), sc *runtime.PodSandboxConfig) (string, error)
 }
 
 type Controller struct {