Support permanently deleting files and directories using Shift+Del

Add a confirmation dialog to limit risks of data lost.

i18n/en/cosmic_files.ftl

@@ -83,6 +83,15 @@ browse-store = Browse {$store}
 other-apps = Other applications
 related-apps = Related applications
 
+## Permanently delete Dialog
+selected-items = the {$items} selected items
+permanently-delete-question = Permanently delete?
+delete = Delete
+permanently-delete-warning = Permanently delete {$target}, {$nb_items ->
+        [one] he
+        *[other] they
+    } can not be restored
+
 ## Rename Dialog
 rename-file = Rename file
 rename-folder = Rename folder
@@ -223,6 +232,14 @@ moved = Moved {$items} {$items ->
         [one] item
         *[other] items
     } from "{$from}" to "{$to}"
+permanently-deleting = Permanently deleting "{$items}" "{$items ->
+        [one] item
+        *[other] items
+    }"
+permanently-deleted = Permanently deleted "{$items}" "{$items ->
+        [one] item
+        *[other] items
+    }"
 renaming = Renaming "{$from}" to "{$to}"
 renamed = Renamed "{$from}" to "{$to}"
 restoring = Restoring {$items} {$items ->