Select list/tile view and store to ui settings

Issue: #526

modules/webapp/src/main/elm/Data/Items.elm

@@ -12,6 +12,7 @@ module Data.Items exposing
     , idSet
     , length
     , replaceIn
+    , unwrapGroups
     )
 
 import Api.Model.ItemLight exposing (ItemLight)
@@ -27,6 +28,11 @@ flatten list =
     List.concatMap .items list.groups
 
 
+unwrapGroups : List ItemLightGroup -> List ItemLight
+unwrapGroups groups =
+    List.concatMap .items groups
+
+
 concat : ItemLightList -> ItemLightList -> ItemLightList
 concat l0 l1 =
     let