Move Chicago Taxi Example Benchmarks to Beam orchestrator

As originally implemented, the Chicago Taxi Example benchmarks for Beam Python SDK rely on on a custom bash script that runs (orchestrates) each of the pipelines that are part of the Chicago Taxi Example.

The TFX team recently developed a Beam-based pipeline orchestrator:  https://www.tensorflow.org/tfx/guide/beam_orchestrator

The example with Beam orchestrator: https://github.com/tensorflow/tfx/blob/master/tfx/examples/chicago_taxi_pipeline/taxi_pipeline_beam.py