First version of new ui based on tailwind

This drops fomantic-ui as css toolkit and introduces tailwindcss. With
tailwind there are no predefined components, but it's very easy to
create those. So customizing the look&feel is much simpler, most of
the time no additional css is needed.

This requires a complete rewrite of the markup + styles. Luckily all
logic can be kept as is. The now old ui is not removed, it is still
available by using a request header `Docspell-Ui` with a value of `1`
for the old ui and `2` for the new ui.

Another addition is "dev mode", where docspell serves assets with a
no-cache header, to disable browser caching. This makes developing a
lot easier.

modules/webapp/src/main/elm/Page/ManageData/Data.elm

@@ -26,16 +26,20 @@ type alias Model =
 
 
 init : Flags -> ( Model, Cmd Msg )
-init _ =
-    ( { currentTab = Nothing
-      , tagManageModel = Comp.TagManage.emptyModel
+init flags =
+    let
+        ( m2, c2 ) =
+            Comp.TagManage.update flags Comp.TagManage.LoadTags Comp.TagManage.emptyModel
+    in
+    ( { currentTab = Just TagTab
+      , tagManageModel = m2
       , equipManageModel = Comp.EquipmentManage.emptyModel
       , orgManageModel = Comp.OrgManage.emptyModel
       , personManageModel = Comp.PersonManage.emptyModel
       , folderManageModel = Comp.FolderManage.empty
       , fieldManageModel = Comp.CustomFieldManage.empty
       }
-    , Cmd.none
+    , Cmd.map TagManageMsg c2
     )