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](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](https://github.com/tensorflow/tfx/blob/master/tfx/examples/chicago_taxi_pipeline/taxi_pipeline_beam.py)

Imported from Jira [BEAM-8892](https://issues.apache.org/jira/browse/BEAM-8892). Original Jira may contain additional context.
Reported by: pabloem.