Manage notification channels separately and migrate

It's more convenient to manage notification channels separately, as it
is done with email settings. Notification hook and other forms are
adopted to only select channels. Hooks can now use more than one
channel.

modules/webapp/src/main/elm/Messages/Comp/NotificationHookManage.elm

@@ -11,7 +11,6 @@ module Messages.Comp.NotificationHookManage exposing
     , gb
     )
 
-import Html exposing (Html, text)
 import Http
 import Messages.Basics
 import Messages.Comp.HttpError
@@ -27,9 +26,6 @@ type alias Texts =
     , httpError : Http.Error -> String
     , channelType : Messages.Data.ChannelType.Texts
     , newHook : String
-    , matrix : String
-    , gotify : String
-    , email : String
     , httpRequest : String
     , hookCreated : String
     , hookUpdated : String
@@ -39,12 +35,8 @@ type alias Texts =
     , reallyDeleteHook : String
     , formInvalid : String
     , invalidJsonFilter : String -> String
-    , integrate : String
-    , intoDocspell : String
-    , postRequestInfo : String
     , updateWebhook : String
     , addWebhook : String
-    , notifyEmailInfo : String
     }
 
 
@@ -56,9 +48,6 @@ gb =
     , httpError = Messages.Comp.HttpError.gb
     , channelType = Messages.Data.ChannelType.gb
     , newHook = "New Webhook"
-    , matrix = "Matrix"
-    , gotify = "Gotify"
-    , email = "E-Mail"
     , httpRequest = "HTTP Request"
     , hookCreated = "Webhook created"
     , hookUpdated = "Webhook updated"
@@ -68,12 +57,8 @@ gb =
     , reallyDeleteHook = "Really delete this webhook?"
     , formInvalid = "Please fill in all required fields"
     , invalidJsonFilter = \m -> "Event filter invalid: " ++ m
-    , integrate = "Integrate"
-    , intoDocspell = "into Docspell"
-    , postRequestInfo = "Docspell will send POST requests with JSON payload."
     , updateWebhook = "Update webhook"
     , addWebhook = "Add new webhook"
-    , notifyEmailInfo = "Get notified via e-mail."
     }
 
 
@@ -85,9 +70,6 @@ de =
     , httpError = Messages.Comp.HttpError.de
     , channelType = Messages.Data.ChannelType.de
     , newHook = "Neuer Webhook"
-    , matrix = "Matrix"
-    , gotify = "Gotify"
-    , email = "E-Mail"
     , httpRequest = "HTTP Request"
     , hookCreated = "Webhook erstellt"
     , hookUpdated = "Webhook aktualisiert"
@@ -97,10 +79,6 @@ de =
     , reallyDeleteHook = "Den webhook wirklich löschen?"
     , formInvalid = "Bitte alle erforderlichen Felder ausfüllen"
     , invalidJsonFilter = \m -> "Ereignisfilter ist falsch: " ++ m
-    , integrate = "Integriere"
-    , intoDocspell = "in Docspell"
-    , postRequestInfo = "Docspell wird JSON POST requests senden."
     , updateWebhook = "Webhook aktualisieren"
     , addWebhook = "Neuen Webhook hinzufügen"
-    , notifyEmailInfo = "Werde per E-Mail benachrichtigt."
     }