[backend][assetmodel] Implement storage property in AssetType

It will return the storage class matching the asset

beat/editor/backend/assetmodel.py

@@ -65,6 +65,11 @@ class AssetType(Enum):
         self.path = path
         self.klass = klass
 
+    @property
+    def storage(self):
+        mod = __import__(self.klass.__module__, fromlist=["Storage"])
+        return getattr(mod, "Storage")
+
     @staticmethod
     def from_path(path):
         for asset_type in AssetType: