Allow to search in soft-deleted items

A new query/request parameter can be used to apply a search to only
soft-deleted items.

The query expression `Trashed` has been introduced which selects only
items with state `Deleted`. This is another option an analog to
`ValidItemStates` (both cannot be used together as they would select
no items). This new query node is not added to the parser, because
users may not use it in their own queries - it must be part of the
"fixed" query so the application can control in which subset to search
(it would otherwise be possible to select any items).

modules/restapi/src/main/resources/docspell-openapi.yml

@@ -1478,6 +1478,7 @@ paths:
         - $ref: "#/components/parameters/limit"
         - $ref: "#/components/parameters/offset"
         - $ref: "#/components/parameters/withDetails"
+        - $ref: "#/components/parameters/deleted"
       responses:
         200:
           description: Ok
@@ -1576,6 +1577,7 @@ paths:
         - authTokenHeader: []
       parameters:
         - $ref: "#/components/parameters/q"
+        - $ref: "#/components/parameters/deleted"
       responses:
         200:
           description: Ok
@@ -4112,6 +4114,12 @@ components:
         withDetails:
           type: boolean
           default: false
+        deleted:
+          type: boolean
+          default: false
+          description: |
+            If this is true, the search performed only for
+            soft-deleted items.
         query:
           type: string
           description: |
@@ -5838,6 +5846,12 @@ components:
       description: Whether to return details to each item.
       schema:
         type: boolean
+    deleted:
+      name: deleted
+      in: query
+      description: Whether to search in soft-deleted items only.
+      schema:
+        type: boolean
     name:
       name: name
       in: path