Removed the divider as a seperate component

Since it's only used in one place, there is no real point in making it a seperate file

CURA-6005

plugins/CuraDrive/src/qml/components/BackupList.qml

@@ -26,10 +26,11 @@ ScrollView
                 width: parent.width
             }
 
-            Divider
+            Rectangle
             {
-                width: parent.width
-                anchors.top: backupListItem.bottom
+                id: divider
+                color: UM.Theme.getColor("lining")
+                height: UM.Theme.getSize("default_lining").height
             }
         }
     }

plugins/CuraDrive/src/qml/components/Divider.qml

@@ -1,13 +0,0 @@
-// Copyright (c) 2018 Ultimaker B.V.
-// Cura is released under the terms of the LGPLv3 or higher.
-
-import QtQuick 2.7
-
-import UM 1.3 as UM
-
-Rectangle
-{
-    id: divider
-    color: UM.Theme.getColor("lining")
-    height: UM.Theme.getSize("default_lining").height
-}