TimerService: make TimerResponse support redirect()

This allows executing a script doing REQUEST.RESPONSE.redirect() without
error.

Before this patch it's an AttributeError similar to:

    ------
    2022-04-12 03:52:49,083 WARNING ActivityTool Could not call method ...
    Traceback (most recent call last):
      ...
      File "Script (Python)", line 34, in Base_redirect
        return request.RESPONSE.redirect(redirect_url, status=status_code)
    AttributeError: TimerResponse instance has no attribute 'redirect'
2 jobs for fix/timerserver-redirect in 0 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-TestRunner2

00:55:54

failed ERP5.UnitTest-TestRunner2

01:45:28