Use a minimum age of items to remove

In order to keep deleted items for a while, the periodic task can now
use a duration to only remove items with a certain age. This can be
used to ensure that a deleted item stays at least X days before it
will be removed from the database.

Refs: #347

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

@@ -40,6 +40,7 @@ type alias Texts =
     , languageLabel : Language -> String
     , classifierTaskStarted : String
     , emptyTrashTaskStarted : String
+    , emptyTrashStartInvalidForm : String
     , fulltextReindexSubmitted : String
     , fulltextReindexOkMissing : String
     , emptyTrash : String
@@ -71,6 +72,7 @@ gb =
     , languageLabel = Messages.Data.Language.gb
     , classifierTaskStarted = "Classifier task started."
     , emptyTrashTaskStarted = "Empty trash task started."
+    , emptyTrashStartInvalidForm = "The empty-trash form contains errors."
     , fulltextReindexSubmitted = "Fulltext Re-Index started."
     , fulltextReindexOkMissing =
         "Please type OK in the field if you really want to start re-indexing your data."
@@ -103,6 +105,7 @@ de =
     , languageLabel = Messages.Data.Language.de
     , classifierTaskStarted = "Kategorisierung gestartet."
     , emptyTrashTaskStarted = "Papierkorb löschen gestartet."
+    , emptyTrashStartInvalidForm = "Das Papierkorb-Löschen Formular ist fehlerhaft!"
     , fulltextReindexSubmitted = "Volltext Neu-Indexierung gestartet."
     , fulltextReindexOkMissing =
         "Bitte tippe OK in das Feld ein, wenn Du wirklich den Index neu erzeugen möchtest."

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

@@ -19,6 +19,8 @@ type alias Texts =
     { basics : Messages.Basics.Texts
     , calEventInput : Messages.Comp.CalEventInput.Texts
     , schedule : String
+    , minAge : String
+    , minAgeInfo : String
     }
 
 
@@ -27,6 +29,8 @@ gb =
     { basics = Messages.Basics.gb
     , calEventInput = Messages.Comp.CalEventInput.gb
     , schedule = "Schedule"
+    , minAge = "Minimum Age (Days)"
+    , minAgeInfo = "The minimum age in days of an items to be removed. The last-update time is used."
     }
 
 
@@ -35,4 +39,6 @@ de =
     { basics = Messages.Basics.de
     , calEventInput = Messages.Comp.CalEventInput.de
     , schedule = "Zeitplan"
+    , minAge = "Mindestalter (Tage)"
+    , minAgeInfo = "Das Mindestalter (in Tagen) der Dokumente, die gelöscht werden. Es wird das Datum der letzten Veränderung verwendet."
     }