async function sync(req, res) {
    await caldavHandler.syncUserCalendars(req.user.id);
    await caldavHandler.syncUserWebcals(req.user.id);
    res.json({
      success: true,
    });
  }
@api {get} /api/v1/service/caldav/sync Start caldav sync for a user
@apiName Sync
@apiGroup CalDAV