Add new field acknowledgement and adjacent visibility fields

Close #11

classes/CsvxmlAvailableFields.php

@@ -501,6 +501,32 @@ final class CsvxmlAvailableFields {
                     ""
                 ),
             ],
+            $tlLoader->tl("object_addendum", "object_add", "acknowledgements") => [
+                "acknowledgements" => new FieldEntry(
+                    false,
+                    [],
+                    ['acknowledgements_md', 'acknowledgements_extern'],
+                    '', # 'If <i>acknowledgements</i> is made available for an object, <i>acknowledgements_md></i> and <i>acknowledgements_extern</i> have to have values too',
+                    $tlLoader->tl("object_addendum", "object_add", "acknowledgements"),
+                    $tlLoader->tl("object_addendum", "object_add", "acknowledgements_explica"),
+                ),
+                "acknowledgements_md" => new FieldEntry(
+                    false,
+                    ["y", "n"],
+                    ['acknowledgements_md', 'acknowledgements_extern'],
+                    'Shall a given acknowledgement be displayed at museum-digital? If <i>acknowledgements</i> is available for an object, <i>acknowledgements_md></i> and <i>acknowledgements_extern</i> have to have values too',
+                    $tlLoader->tl("object_addendum", "object_add", 'besch_visibility_md'),
+                    ""
+                ),
+                "acknowledgements_extern" => new FieldEntry(
+                    false,
+                    ["y", "n"],
+                    ['acknowledgements_md', 'acknowledgements_extern'],
+                    'Shall later exports from museum-digital inlude acknowledgements? If <i>acknowledgements</i> is available for an object, <i>acknowledgements_md></i> and <i>acknowledgements_extern</i> have to have values too',
+                    $tlLoader->tl("object_addendum", "object_add", 'besch_visibility_extern'),
+                    ""
+                ),
+            ],
             $tlLoader->tl("basis", "basis", 'administration') => [
                 "inclusion_when" => new FieldEntry(
                     false,