Improve performance of LocalStorage._list_blobs

Current implementation globs over the entire root directory, but needs
files only with the given prefix. Globbing over the entire root
directory is very slow in case of a large number of files. 'Path.resolve()'
is used in an attempt to protect against directory traversal.

Author: alkur-gh

medusa/storage/local_storage.py

@@ -51,12 +51,10 @@ def disconnect(self):
     async def _list_blobs(self, prefix=None):
         if prefix is None:
             paths = list(self.root_dir.glob('**/*'))
+        elif str(prefix).endswith('/'):
+            paths = list(self.root_dir.joinpath(prefix).resolve().glob('**/*'))
         else:
-            paths = [
-                p for p in self.root_dir.glob('**/*')
-                # relative_to() cuts off the base_path and bucket, so it works just like cloud storages
-                if str(p.relative_to(self.root_dir)).startswith(str(prefix))
-            ]
+            paths = [p.resolve() for p in self.root_dir.glob(str(prefix) + '*/**/*')]
 
         return [
             AbstractBlob(