Added sorting by brand to MaterialsModel.

Contributes to issue CURA-4243.

cura/Settings/MaterialsModel.py

@@ -1,6 +1,7 @@
 # Copyright (c) 2017 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
 
+from typing import Any, List
 from UM.Settings.ContainerRegistry import ContainerRegistry #To listen for changes to the materials.
 from UM.Settings.Models.InstanceContainersModel import InstanceContainersModel #We're extending this class.
 
@@ -23,3 +24,10 @@ class MaterialsModel(InstanceContainersModel):
     def _onContainerChanged(self, container):
         if container.getMetaDataEntry("type", "") == "material":
             super()._onContainerChanged(container)
+
+    ##  Group brand together
+    def _sortKey(self, item) -> List[Any]:
+        result = []
+        result.append(item["metadata"]["brand"])
+        result.extend(super()._sortKey(item))
+        return result