[Notebook] Create a parameterize script for OracleToSpanner

[tanyarw]

Enable OracleToSpanner_notebook to be executed from the command line.

1. Create a script like this to execute the notebook with command line arguments.

2. Update the notebook to use IS_PARAMETERIZED variable as a flag for cells containing parameter fields and working directory field.

3. The cell containing IS_PARAMETERIZED = False must be cell-tagged as parameters

4. Update parameterize_script/script_name.py with the script name

5. Update run_notebook.py to include ScriptName

6. Update both README.md files

7. Fix WORKING_DIRECTORY in notebook from /python to /java

Refer this PR: #766