Merge branch 'renovate/configure' into 'master'

Configure Renovate

See merge request Teckids/schul-frei/edugit/meet.edugit.org!1

renovate.json

+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:base"
+  ],
+  "ignorePresets": [
+    ":prHourlyLimit200"
+  ]
+}