[VanillaBiometrics] Make some dask arguments visible in the CLI commands
Sometimes our heuristics that defines
n_workers is not enough to cover all range of problems.
In this MR I'm adding the options
--dask-n-workers in the
vanilla-biometrics CLI command, so that users can explicitly set, respectively, the dask bag partition size and the number of workers to start an experiment without having to play around with the API.