As a DS user, I need to be able to easily execute Python script files so I can test the components needed for model serving.

As part of the model serving best practice template, we are recommending that users capture their predict model in a separate prediction.py file. Elyra has a Python script editor plugin that enables users to edit and run Python scripts from within JL. While we're not planning to support Elyra in the near term, we'd like to implement a Python script editor plugin to help simplify the model serving process. 

This story is a follow on to the Spike: RHODS-311