Resolve "Wiki in Einrichtung kann keine Startseite haben"

Closes #4992

Merge request studip/studip!3746

db/migrations/5.5.29_biest4992_wiki_startpage.php

+<?php
+
+class Biest4992WikiStartpage extends Migration
+{
+    public function description()
+    {
+        return 'Changes the range of the WIKI_STARTPAGE_ID config to match courses and institutes.';
+    }
+    public function up()
+    {
+        DBManager::get()->exec("
+            UPDATE `config`
+            SET `range` = 'range'
+            WHERE `field` = 'WIKI_STARTPAGE_ID';
+        ");
+    }
+
+    public function down()
+    {
+        DBManager::get()->exec("
+            UPDATE `config`
+            SET `range` = 'course'
+            WHERE `field` = 'WIKI_STARTPAGE_ID';
+        ");
+    }
+}