Adding List(path) to object storage definition and accompanying definition to fs

pkgs/storage/storage.go

@@ -1,7 +1,13 @@
 package storage
 
 type ObjectStorage interface {
-	GetList() ([]byte, error)
+	List(path string) ([]ObjectDescription, error)
 	Get(path string) ([]byte, error)
 	Put(path string, object []byte) error
 }
+
+type ObjectDescription struct {
+	Path  string
+	IsDir bool
+	Hash  string
+}