Fix deprecated client to work with kfp-server-api 2.0.1

The deprecated client is currently broken, as it refers to APIs that
don't exist anymore. This change makes things less broken, but there
might be more fixes needed.

Basically:

1. Job -> RecurringRun
2. adapt code from current client that warns for FOO_job() and
   forwards to FOO_recurring_run()
3. adapt some code from create_recurring_run()
4. version the APIs: "Api" -> "V2beta1"

Signed-off-by: Rudi C <[email protected]>