Add possibility to disable TimingAuditor, disable it in all tests

The Brunel QMTests do not check changes to the TimingAuditor output and are in any case too short for the timing numbers to have any meaning. Conversely, whenever the test references are updated, the diffs become huge because of changes to the TimingAuditor output. I think therefore that it would make sense to switch off the TimingAuditor altogether in the QM tests, while leaving it on by default for all other use cases (interactive and production jobs, LHCbPR tests etc.)

Also modified all tests to include the options file testBrunel-defaults.py