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/Queue/Data.elm

@@ -1,6 +1,7 @@
 module Page.Queue.Data exposing
     ( Model
     , Msg(..)
+    , QueueView(..)
     , emptyModel
     , getDuration
     , getRunningTime
@@ -27,9 +28,18 @@ type alias Model =
     , showLog : Maybe JobDetail
     , deleteConfirm : Comp.YesNoDimmer.Model
     , cancelJobRequest : Maybe String
+    , queueView : QueueView
     }
 
 
+type QueueView
+    = CurrentJobs
+    | QueueAll
+    | QueueWaiting
+    | QueueError
+    | QueueSuccess
+
+
 emptyModel : Model
 emptyModel =
     { state = Api.Model.JobQueueState.empty
@@ -41,6 +51,7 @@ emptyModel =
     , showLog = Nothing
     , deleteConfirm = Comp.YesNoDimmer.emptyModel
     , cancelJobRequest = Nothing
+    , queueView = CurrentJobs
     }
 
 
@@ -55,6 +66,7 @@ type Msg
     | DimmerMsg JobDetail Comp.YesNoDimmer.Msg
     | CancelResp (Result Http.Error BasicResult)
     | ChangePrio String Priority
+    | SetQueueView QueueView
 
 
 getRunningTime : Model -> JobDetail -> Maybe String