Added saving and filling buttons from file.

TODO: Fix too long names and add functionality that removes buttons that are removed from list

modules/padslist/model.py

@@ -0,0 +1,10 @@
+from dataclasses import dataclass
+from dataclasses_json import dataclass_json
+from typing import Dict
+
+
+@dataclass_json
+@dataclass(frozen=True)
+class PadsModel:
+    first_pads: Dict[str, str]
+    second_pads: Dict[str, str]